Try applying all the pre SP3 patches:
Q300845_W2K_SP3_X86_EN.exe
Q311967_W2K_SP3_X86_EN.exe, Click reboot later and continue
Q313829_W2K_SP3_X86_EN.exe, Click reboot later and continue
Q314147_W2K_SP3_X86_EN.exe, Click reboot later and continue
Q318593_Group Policy.exe, Click reboot later and continue
Q320206_W2K_SP4_X86_EN.exe, Click on “do not restart now” and finish
q321232_IE6-PATCH.exe
vbs56nen_MS02-009.exe
Q318203_MSXML30_x86.exe
rbupdate.exe
You can find all these patches from Microsoft site.
Cheers!!
Hassan