Laptop freezes before boot

[cremson]

Hello.
I own a A300-1GT Toshiba Satellite pro.

The problem i have is that my laptop freezes after a random period of time after boot. It then shuts down for a few seconds and then starts up again.

The thing is if i manage to log in to windows and start a resource havy application the laptop runs normaly until i shut it down. Also, if i boot in safe mode it runs smoothly.

I tried replacing the RAM , and it still does the same thing. I opened it up, cleaned it,replaced the thermal paste. I did a clean install of both legitimate win xp and win 7.

 

[smorizio]

try running hdtune and a hard drive vendor tools and see if your hard drive is fine. (smart). if the hard drive or hard drive controller is having issues it can cause the system to reboot and do strange stuff.

 

[cremson]

I ran th WD diagnostic tool (manufacturer) and Sea tools from seagate and all test were good.

Any other suggestions?