WinXP msgina.dll & shlwapi.dll problem

[Anita]

After I install the XP SP1 my PC won't boot up. It gives
me winlogon.exe entry point not found. Procedure
associsdangerous could not be located in DLL library
(shlwapi.dll)
User interface failure - Logon interface msgina.ll failed
to load. I tried to use my recovery cd, but it didn't
show my last backup to restore. I don't want to restore
to factory settings and lose all my data.

Please help.