I have had no luck with restore function on my computer. I run windows xp pro. It does not restore to any date.
First of all check your disc space... if it's running low, you'll have to make some room for the SR to work.
Second option: check the System Restore Service; It may be disabled.
Third option: Scan your system for virus/trojans... sometimes SR doesn't work due to virus infection. If the scan doesn't fix SR, you may have to disable it to remove corrupted SR files. Check this cause here: http://support.microsoft.com/kb/831829
To disable System Restore; Control Panel \ System Restore \ check Disable SR, restart the system and reenable System Restore.