Hey Folks,
As some of you suggested, I uninstalled the firefox completely and downloaded it again.
And guess what..
now its opening withing 10 secs..
WOW.. i'm soo happy now.. I didnt have any other complaint except this so when it is removed, Im glad to be back on track. I couldnt wait that long for a browser to open. Rest is great with FF.
Ya I've tried almost every browser including chrome but I think FF is still the best!