being a dell you should have an option to do a system recovery.there should be a recovery partition on your hard drive.dell support should help you.
Update: Booting is fine now, but still shuts down on normal mode after 5 to 15mins, things run smoothly on safe mode. Seems like a driver issue don't you think?
or hardware related?getting out of my league here.drivers would be easiest to try first,although win 7 has a pretty good selection of drivers and should at least install default ones that work.i had a similar problem with win 7 when i tried to run the windows experience index.it would run for a minute and then the computer would shut down.it turned out my video card was overheating and dying.i took the fan off and cleaned and regreased the heat sink and it was good to go.it might also be time for you to consider cleaning and applying thermo paste to your cpu as well.to me this sounds like a hardware problem.maybe someone else can chime in here.
check in bios to see if has cpu temp reading & if does then leave it on to see what the cpu temp goes to. manuals link http://support.dell.com/support/edocs/systems/ins1525/en/index.htm
It seems that I was mistaken, it also shuts down on safe modes. I posted on dell community, the said that the only way to restore it, is to buy another hard drive. EDIT: I don't think it's a overheating issue, I touched the bottom of laptop and air vent, it's not hot at all, and still restarts/shut down by itself.
Update: Sorry for the late reply, temperature is 53C, and it seems to run quite fine, when running ONLY Chrome and some other programs like CCleaner or so, when converting videos/playing games/watching videos, etc. well it shuts down after a little while.
your cpu is overheating. know anybody with an air compressor so can give the laptop blasts of air especially the cpu heatsink & fan assembly?
Actually I don't. And another one, once the laptop restarts, it will get a consecutive restarts, sometimes Blue Screen.