When you get that screen, if you click on Open, what happens?
In my mind clearly you have some type of computer problem, as you have stated in your original post. What that is I have no idea because you haven't bothered explaining it.
Computer problems are caused by several different things.
1) Some type of hardware failure which could be RAM, hard drive or the system is overheating because of dust or a failure of a fan.
2) some type of virus or malware.
Please explain the computer problems you are having.
If after you get that screen you posted above what exactly happens when you select that catalog and click Open. Be exact in what happens next.
You write, "get a comment that my lightroom catalog is not there," but the screenshot clearly shows that a catalog is there, exactly where it should be - in the default location. Were you expecting to see a different catalog or several catalogs?