Some time ago, my new computer got infected by a virus thanks to a mistake by my wonderful wife. I thought I’d taken care of all of the side effects.

Apparently, however, I hadn’t. I discovered that I wasn’t able to access Media Player’s help, or reinstall the product. (This is all because I found that I couldn’t play a video clip.)

In the process of troubleshooting, I found some more system files that I couldn’t access because nobody had rights to them and the owner wasn’t known. (This is what happened to some DLLs previously.) In order to correct things once and for all, I took ownership of every single file in the Windows directory, then replaced all existing rights to be those inherited from the root directory.

I haven’t had any problems since. Hopefully, this fixed things once and for all.