When trying to install I was informed that I would need IIS installed also. So I searched for my Windows XP SP2 disc and started the update.
It didn't get that far, I was asked for a file staxmem.del_ all the time and although it was on the disc it wouldn't accept it.
The solution I found is running this command from Start > run (windows key + R)
esentutl /p %windir%\security\database\secedit.sdb