I recently downloaded Windows 8.1. My computer purchased in 2012 came with Windows 7 preinstalled and I "upgraded" to Windows 8 via disc. After I downloaded 8.1 my desktop blacked out and I could only get on the net from the start button. Progams seem to work when they want to and the entire system is interminably slow. I'm confident the system is virus free. Have others experienced these types of problems after downloading 8.1 or am I just lucky?