Thanks for your help! I had exited Mcafee but forgot Microsoft security essentials real time protection was running so I toggled it off and ran the installer again, it eventually installed but I did get an error about being unable to update a certain file and restarted and finished installing, but not before getting the sharing violation error one more time.
I ran the repair and restarted and Windows seemed to start up more quickly, but I'm still experiencing bouts of unresponsiveness when navigating from file to file. Going to run it again in just a bit after doing the optional file checks that I skipped the first time. Also probably going to download Microsoft's free Anti-Virus software and see if that helps. Not sure if Microsoft's AV is better than Mcafee, but I've heard good things.
Thanks again!