Windows Wont Start normally Keeps Restarting

I have Windows 7 Ultimate installed on my laptop. It Worked Fine However now has begun to give problems. It is within the company guarantee but the OS is not covered.
Each time I try Starting the computer It displays the Intel Screen and then it goes BAM.. Keeps repeating the same process again and again. I am confused with regard to what is wrong. The service center guys tell me that Software damage is not covered.
Help needed .
Thanks
