winxp boot failure

Recently, I used winxp’s (professional edition) system restore feature, but during the process the machine was shut down due to power failure. When I tried to boot up again winlogon.exe was unable to execute due to some .dll file missing. The machine keeps on restarting and showing the same message. Is there any possible way of solving this problem without actuatlly reinstalling the OS? btw, system recovery tools and installer cd’s are not available with me. need help, thanks!