Windows reset?

Consider saving your files and bookmarks to an external drive, then formatting the C drive and reloading the latest version of windows that your system can support. Sometimes there is no magic fix and only a fresh start works.

Remember, it is often less time consuming to reload than to spend days troubleshooting. Just ensure you have the programs (and magic codes) you need before you wipe it out.

However,,,,,, I had a bad video card recently and the problems were very weird (and did not indicate the video card in any way ) Problems much the same way as yours. Some files disappeared, computer would not restore, boot up was unstable, etc.
This is what I did. Spent a good portion of yesterday saving stuff, reformatting, and then installing programs. All is good so far and it is much more snappy now.