What error message if any do you get? What happens when you try and restore?
Turn off System Restore by right clicking My Computer | System Restore.
Before turning it back you need to make sure the SVI folders are empty. This
folder or folders are hidden by default. Open control panel | folder options
and click "show hidden files and folders" and remove the tick by "hide
protected operating system files". You will also need to take ownership of
the folder (see below).
Left click the folder and delete all files and folders from within. This
will get rid of any corrupted data. Turn System Restore back on. A restore
point will be created automatically. Test it by trying to restore it. If it
restores you solved the problem.
If it wont restore you will need to reinstall system restore. Do this by
searching for a file called sr.inf. You will need to search for hidden files
and system files. It is located in a folder in C:\Windows\inf (or whatever
drive windows is installed to). Right click sr.inf and choose install. You
will probably need your windows install CD. After reinstalling, test system
restore again. Repost if you need more help.
Take Ownership of Files and Folders
http://support.microsoft.com/default.aspx?scid=kb;en-us;308421&sd=tech