Files cant be found

When I download any file off the internet or even try to save a picture from Reddit/Facebook, I go to open it and it says Windows can not find C:\User\XXXXXXXXX\Downloads etc etc

It has only been doing this for the past week or so, and the PC is not even a month old. What happened?  

Now even some Windows files wont open. I went to the Registry Director (Regedit.exe) and even that wont open. It says Windows cannot find C:\Windows\regedit.exe

I cant open about 90% of the files on my computer because it "cant find the file" it says to retype the name carefully and try again or make sure I spelled it correctly...

Virus Scans show nothing malicious on the PC

edit: Many of my files cant open. I have basically only been able to open games, no other files/applications beside Chrome