System Runtime InteropServices.COM Exception error message

I have been having a terrible time, from the past few days. My PC which was running Windows XP had an infection and corrupted most of the Windows files and drivers.
I had to literally clean it up and upgrade it to Windows Vista, for more security reasons. Now when I try to open a web application project, which is set up to use IIS, I get an error message. I have MS visual Studio 2008 installed on my machine and I am logged in as admin.
Can someone explain me step by step manner of how to resolve this issue?
Microsoft Visual Studio
System.Runtime.InteropServices.COMException
