Hi,
How did you update? Did you download the SP2 then installed it manually?
Make sure you are trying to install the correct architecture(32-bit or 64-bit):
Service Pack 2 for Microsoft Office 2010:
http://www.microsoft.com/en-au/download/details.aspx?id=39667 (32 bit)
http://www.microsoft.com/en-au/download/details.aspx?id=39647 (64 bit)
If you still have trouble, try updating in a clean boot state:
http://support.microsoft.com/kb/929135/en-au (don't forget to return to normal boot when finished).
As the description is simple, if the problem persists please let me know what the error message is.
Regards,
Melon Chen
TechNet Community Su