Windows won’t do reinstall

Ok I have a serious problem… I recieved a computer froma one of our clients and all I should do is install SP2 for XP. However the computer stopped responding in the middle of the installation and all I could do is reset the computer. But now it won’t boot to windows. Instead it keeps resetting itself. I tried Repairing the installation and the text portion of the setup goes fine but when it reboots insted of continuing to second phase of setup it wants to boot to windows again and it still keeps resetting. Neither safe mode or Last known good configuration helps. Any ideas?

Regards,
Vlado