Every other week I have noticed this happens now. I’ll be logged on for a few hours and then suddenly the monitor goes blank and my pc restarts?
What could be the problem guys?
Re: -- Computer restarts automatically? --
One of the hardware's driver is messing up... Have you installed a new hardware or updated some driver in last few days?
Re: -- Computer restarts automatically? --
install a new user. 
joke aside, there could be several reasons like driver problem or processor over heating.
Re: -- Computer restarts automatically? --
download everestand check ur temprature (cpu/hd) and then post back
also read you event viewer log and look for the application log and system log around the time it died and see if u see anything obvious
Re: -- Computer restarts automatically? --
^ Yes, mostly software or driver problem. Temperature can be another issue. Electric fluctuation is one reason, too.
Re: -- Computer restarts automatically? --
can u see a specific pattern? like "no more than 5 hrs and computer restarts" ?
if its random.. then its more "likely" to be a driver/lota trouble.. if its patterened.. then chances are its gonna be heating issue..
Re: -- Computer restarts automatically? --
utha kar bahir phenko
Re: -- Computer restarts automatically? --
- Try changing your CPU fan 1st
- If the problem persist replace power supply
- If 1 & 2 doesn’t work then fresh install OS (Format HDD)
- If 1, 2 & 3 doesn’t work then replace the processor
Re: -- Computer restarts automatically? --
- If 1, 2,3 & 4 doesn’t work then change your internal wiring in house or change the house.
Re: -- Computer restarts automatically? --
hhahaha… bechara…
luc… sab ko chor… event log ki entries bata..
go to start -->run and type in “eventvwr.msc” and hit enter
check the application, system and security logs around the time computer reboots…
and then report here..
i have another tool to analyze… i will tell ya abt that when u tell me who picked your ashes fantasy cricket team…
Re: -- Computer restarts automatically? --
I have the same problem. The computer just restarts itself out of the blue. No regular pattern.
I’ve tried reinstalling and formatting the C-drive, so I’m afraid it’s a hardware issue. But I don’t have a clue which hardware piece it could be. 
Re: -- Computer restarts automatically? --
check ur cpu temprature with the program I mentioned. i have seen this to be a most common factor, at least with my two pcs in the past. I have a tendency of putting a little too much hardware for the power supply to handle. if the temprature is hight but the fans are working fine then its pretty obvious that powersupply is due for an upgrade. in most bios settings, the computer is configured to restart itself when the temprature reaches a certain point.
Re: -- Computer restarts automatically? --
If your computer re-starts after every, lets say 5 or 10 mints, then it could also be the RAM issue.
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I've been using Everest for a few months, but I didn't know that it shows you the CPU temperature. :)
Right now it is 62° C (144° F). What should be the normal temperature?
Re: -- Computer restarts automatically? --
62 deg C… thats too much Umer Bhai…
normal temp is between 35 to 40 Deg…
p.s. how did you write degrees ( i mean the circle over 62 )
Re: -- Computer restarts automatically? --
anything below 60 is normal or so I have heard. mine used to be around 65 (and crashed periodically) until I added HD fans and replaced my powersuply to handle more load.
Re: -- Computer restarts automatically? --
Umer,
Keep in mind that the onboard measurement facilities are often inaccurate and may report temperatures that are too low. This is especially the case with motherboards that use a thermal sensor below the CPU to "guess" the CPU temperature. The temperature values displayed by the BIOS have usually a correction value added, to compensate for this problem - but in some cases this correction value may be too low, or the sensor might not be in good contact with the CPU
This means: If the maximum allowed temperature for your CPU is 95°C, and your motherboard reports a CPU temperature of 90°C, then you are not on the safe side
However, this doesn't mean that you should start to panic when your CPU reaches 60 degrees celsius, for example. Most people tend to underestimate normal CPU operating temperatures - maybe due to overclockers bragging with their super-low CPU temperatures
Also, overclocked CPUs may run unstable even if their temperature is way below the maximal specified temperature
If your cooler is insufficient and the temperature exceeds the maximum operating temperature, then this does not mean that the CPU is automatically damaged. With AMD CPUs, you will usually encounter crashes if the CPU is overheated; but these go away as soon as the CPU is cooler again. In the long term, running the CPU at a temperature that is too high may reduce the CPU life, since an overheated CPU is more prone to electromigration - even if it runs stable. With P4 CPUs, the CPU will turn its speed down automatically when it overheats. No damage to the CPU is possible, but the system will get slower while it's hot (which, in some cases, users might not even notice)
If you attempt to operate a CPU without heatsink at all, recent AMD CPUs will usually be permanently damaged within seconds, unless special protection is available on the motherboard (Like IBM S5X series). P4 CPUs will run excessively slow without cooler
Umer, you may or may not have encountered cooling-related websites, which states lower temperatures typically correspond to better products. Well to bust the bubble of surprise, the opposite is true: The higher temperatures a CPU can withstand, the less cooling is required. CPUs with low electrical power, but high temperature rating can be used with more quiet and more compact coolers. An example for such a CPU is the Pentium-M, which dissipates less than 25 watts, but may reach temperatures of up to 100°C. The worst-case example is the Pentium 4 Extreme Edition 3.46GHz, which dissipates over 110 watts, but may only reach a maximum temperature of 66°C. Obviously, you need a large and possibly loud cooler then...
Rest is later on CPU theory, hope you got the idea...
Todd
Re: -- Computer restarts automatically? --
Below you can find the list of CPUs with the Max temp (Umer and LUC just in case if you are wondering where to look for... let me make your experience a little better ;))
AMD Athlon, Athlon 64, Opteron, Duron and Sempron
All Slot A CPUs (Athlon classic, Athlon Thunderbird) 70°C
Athlon Socket A up to 1 GHz, Duron up to 1.3GHz 90°C
Athlon "Thunderbird" Socket A 1.1GHz or more 95°C
Athlon MP 1.33GHz or more 95°C
Athlon XP up to 2100+ 90°C
Athlon XP 2200+ and faster 85°C
Duron "Applebred" 1.4G and faster 85°C
AMD Opteron 69 or 70°C depending on model
Athlon 64, 64FX, Sempron Most models 70°C; 65°C for some Socket 939 Athlon 64 models
Athlon 64 X2 (dual core) 65°C
AMD K6 series
All K6 CPUs (166-300MHz) and most K6-2/K6-III CPUs 70°C
K6-2/K6-III CPUs, model name ending with X (e.g. K6-2-450AFX)65°C
K6-2-400AFQ (uncommon) 60°C
K6-2+, K6-III+, most mobile K6/K6-2 CPUs 85°C
mobile K6/K6-2 model name ending with K (e.g. mobile K6-2-P-400AFK) 80°C
The temperatures specified for AMD CPUs max case surface temperatures. These CPUs do not have an internal diode to measure CPU temperature. The accuracy of the CPU temperature measurement depends on the motherboard; therefore, it is possible that the CPU overheats even though the CPU temperature reported by the motherboard is below the specified maximal temperature
Intel Pentium III
Pentium III Socket 370 500-866MHz,
Pentium III Slot 1 (first generation, OLGA) 550-600MHz,
Pentium III Slot 1 ('Coppermine') 500-866MHz 80-85°C depending on model
Pentium III Socket 370 and Slot 1, 933MHz 75°C
Pentium III Slot 1 933MHz 60°C
Pentium III Slot 1 1GHz 70°C for newer versions 60°C for older version
Pentium III Slot 1 1.13GHz (first version) 62°C
Pentium III max temperatures are the maximum temperatures reported by the thermal junction inside the CPU
Intel Celeron / Celeron
Celeron 266-433MHz 85°C (max. CPU case temperature)
Celeron 466-533MHz (0.25µ) 70°C (max. CPU case temperature)
Celeron 533-600MHz ('Coppermine) 90°C
Celeron 633 and 667MHz 82°C
Celeron 700-850 MHz 80°C
Celeron 900MHz-1.4GHz 69-70°C depending on model
Celeron 1.7GHz and faster 67-77°C depending on model
Celeron max temperatures are the maximum temperatures reported by the thermal junction inside the CPU, unless otherwise specified
Intel Pentium II
Pentium II (1st generation, 'Klamath') 72-75°C depending on MHz
Pentium II (2nd generation, 2.0V core), 266-333MHz 65°C
Pentium II (350-400MHz) 75°C
Pentium II (450MHz) 70°C
Pentium II temperatures are the maximum temperatures of the thermal transfer plate (on which the heatsink is installed)
Intel Pentium 4, Pentium 4 Extreme Edition, Pentium M
Pentium 4
Max. temperature depends much on model and clockspeed, but no clear pattern is visible. Consult Intel's tech specs for information on your particular model
Lowest: P4 Extreme Edition 3.2GHz with 64°C
highest: P4 Willamette 1.8GHz with 64°C - 78°C
Pentium M 100°C (!)
Intel Pentium Pro
Pentium Pro, 256 or 512K L2 cache 85°
Pentium Pro, 1MB L2 cache 80°C
Pentium Pro temperatures are maximum surface temperatures
Re: -- Computer restarts automatically? --
Thanks everyone for the detailled explanations.
I think I have narrowed down the problem. There are two fans in my computer, one CPU fan and one System fan. The CPU fan seems to be working fine at around 3000 RPM, but the System fan is not moving at all. No rotation.
And the System fan is sitting inside the powersupply, so I guess that is what I need to replace.
Re: -- Computer restarts automatically? --
Umer, yep replace the power supply.