Can't open AsIO.sys!! (2)

[Damo Gets]

Can anybody tell me how I might be able to fix a message that pops up,
apparently from the 'Security Center', judging by the blue and yellow
shield icon, in a dialog box that says "Can't open AsIO.sys!!(2)"?

I've had this issue ever since I upgraded my copy of Windows 7 from a
version that I was using to test it out to a legitimate copy of Home
Professional that I could pick up with my student discount. Popping
the disc in and selecting 'repair this installation' doesn't seem to
do a thing to help it out. :(

Thanks in advance for any advice you might be able to offer or more
information regarding this problem! I'm really lost in Windows
environments!

-Damon