Solved Pre release of Windows Vista HP will expire in 0 hours..(help)

I've got problems with my OS...

there's always a pop up msg saying that"the pre release of windows vista home premuim will expire in 0 hours.Back up your files and install any release edition of windows vista home premuim"
...2 hours after I receive that msg. my pc restrarts....my windows detected a problem and needs to restart...

How to do the process is my problem..I have read notes how to uninstall my pre-release version. After I uninstall it what shall i do then?

need help...thanks...do I need some installers to update my OS?any help is highly appreciated....

Save your data
Uninstall the pre-release version
Format your hard drive and install a legitimate version.

thank you...