i tried to install a game and during installation my system turned off and restarts and shows a destop for 2 seconds and after that shows a blue screen for few seconds again to restart and process goes on.and this cycle repeats in all modes including safe mode. i think windows vista has crashed. and there is no cd or dvd in dvd rom. i dont know why it has gone to infinite cycle of restart. do i have to reinstall windows vista again and if i install vista again does it mean i m going to lose all data in my hard disk. please tell me what to do ?

sorry i dont quite know vista all that well, but after your pc goes past the POST, repeatedly press F8 until you get to a menu

(now this is where my knowledge is sketchy)..somewhere on the menu there should be something like, "disable restart on system error" or something like that, select that and that will let the bluescreen appear on your screen for longer then 0.000000001 seconds..

somewhere on that bluescreen *should* have details for what file is causing you greif - from there, well yeah we can go from there.

else - i would hook your hdd up to another pc as a slave, get any info you want off and yeah...

goodluck