you could use safe mode with command prompt:
Start the System Restore tool at a command prompt click here
1. Restart your computer, and then press F8 during the initial startup to start your computer in Safe Mode with a command prompt.
For additional information about the Safe mode with a command prompt, click the following article number to view the article in the Microsoft Knowledge Base:
315222 (click here) A description of the Safe mode boot options in Windows XP
2. Log on to your computer with an administrator account or with an account that has administrator credentials.
3. Type the following command at a command prompt, and then press ENTER:
4. Follow the instructions that appear on the screen to restore your computer to an earlier state.
And again: click here
How Do I Perform A System Restore From Safe Mode With Command Prompt Option
If a problem occurs and your pc crashes one way of getting things back to normal is to use System Restore. This is fine so long as you can boot your machine to the desktop, but what happens if you are unable to boot to the Windows XP desktop. Well you now have two options. The first is to reboot your machine, hit the F8 button and then select the Safe Mode option from the onscreen menu. Once in safe mode you can then access system restore just as you would normally from the Windows XP desktop (Start>Accessories>System Tools>System Restore). But what happens if you can't get into Safe Mode? Well you opt for the Safe Mode with command prompt option.
1/ Re-boot your PC
2/ As the PC is booting up keep tapping the F8 button
3/ When the Option Menu appears on screen select the Safe Mode with Command prompt option
4/ At the safe mode command prompt type: %systemroot%\System32\restore\rstrui.exe
5/ System Restore will now open and you can choose the relevant restore point