If you get an error about the Cryptographic services when trying to apply the Security Updates or Service Pack 1,
run the following from Start / Run - note, you might want to just cut and paste the text.
net stop cryptsvc
ren %systemroot%\system32\catroot2 oldcatroot2
net start cryptsvc
regsvr32 softpub.dll
regsvr32 wintrust.dll
regsvr32 initpki.dll
regsvr32 dssenh.dll
regsvr32 rsaenh.dll
regsvr32 gpkcsp.dll
regsvr32 sccbase.dll
regsvr32 slbcsp.dll
regsvr32 cryptdlg.dll