The PC would not shut down and I was forced to swithch off/on.
On switch on McAfee Security Centre would not load.
I tried to reload from a restore point by running "Help and Support", and was unable to run the function.
Restarted in Safe Mode with same result.
Restarted in safe Mode with Command Prompt.
Tried to run it at the command prompt.\Documents and Settings\Administrator>%systemroot%\system32\restore\rstrui.exe
Nothing appears to run and comes back to the Command Prompt.
PC has XP SP3