Can not load IE after loading Svc Pack 3

Hello,
Just wondering if any one can help. We got a virus in our computer which took out some Windows files. The IT guy repaired the files but only to Service Pack 2. I updated through the Windows website to get Service Pack 3 and since then, I can connect to the Internet by way of Mobile Broadband but when I click on 'Internet Explorer', it does nothing, it goes nowhere and doesn't even load a web page.
How do I get the Internet browser back?
Pleeeeeeeeease can someone help?
Thanks heaps
K