System restore tab gone after microsoft update...

After a Microsoft update in XP pro, after rebooting, a
message come up saying it was needful to re-install XP-
pro. After the re-installation the 'System Restore' tab in
the control panel's 'system' icon was missing. When I try
to 'execute' from the 'start'-'run' command-line, I get
this error
" Procedure entry point remote assistant prepare system
restore could not be located in the dynamic link library
winsta.dll"
I have done a search in the knowledge base but could not
find a specific issue relater to this error code, and
similar issues did not seem to restore the 'system
restore' function. Any suggestions??? Thanks Tony Dewar