I have a Precision M6300 with XP pro SP3. I downloaded a zip app (7zip?) that I believe allowed access to other sites (I'm sure I helped it). After this exercise, I tried running Norton Security Suite to verify the allowed access didn't lead to something. The scan would hang at a file and I couldn't cancel the scan without rebooting. After rebooting, I ran Registry Cleanup and it deleted 262 files, which turned out to be icon file extension data (so now most of my links are broken) among other important stuff. Device Manager and Network Connections windows are blank, and I cannot open any internet browsers.
How bad did I mess it up?