|If you've only just reformatted XP and you suspect a virus already you might be better off reformatting again before you get too many of your programs back on there.|
Having said that, I don't know why you are assuming a virus. There are a lot of hits in Google if you use the string "0x80072EFE from Windows Update". Most seem to refer to connection issues and a Proxy Server. If you don't use one then it would be worth looking in IE > Tools > Internet Options > Connections > LAN settings button and make sure "use a proxy server....etc" is unticked.
How to know you are getting old 6:
You can't remember what it is that you have forgotten.