What can i do to stop it. It freezes and the only thing i can do is hold the off button in to shut it down, and then i have trouble starting it up again. Any suggestions PLEASE....

virus?

Virus scan
Run a memcheck CD-rom to make sure your memory isn't shagged.
Make sure you've cleaned the vent holes of dust (? overheating)
Install a program like Speedfan and keep an eye on the CPU temperature
Check the error log when you reboot
Try starting in safe mode....

have done full scan cum up clean.

new laptop then

Likely something badly behaved running in the background grabing resources and not releasing them.
Download a copy of hijackthis and clear out everything except the stuff you really use.

http://www.spywareinfo.com/~merijn/programs.php


If that dosen't work if you have any Norton/Symantec software uninstaling that.