Hi Strike,
Open Windows\System32 folder and check the Version information for these
files:
authz.dll
ntkrnlpa.exe
ntoskrnl.exe
user32.dll
win32k.sys
winsrv.dll
ntkrnlmp.exe (in Windows\system32\dllcache)
If all of the above File Version read as "5.1.2600.2622", then the KB890859
is properly installed. File Information details for this update are given
under section "Security Update Information" in this bulletin:
http://www.microsoft.com/technet/security/Bulletin/MS05-018.mspx
Additionally, see if the Windows Update log gives any additional
information. The log file names are:
"Windows Update.log" in %Windir%
"ReportingEvents.log" in %Windir%\SoftwareDistribution
Open "ReportingEvents.log" file in Notepad, and see if it contains the
following line or similar.
"Installation successful and restart required for the following update:
Security Update for Windows XP (KB890859)"