Not sure what's going on or if I should be worried about this but when I got up today and checked my PC (I had left it on while watching videos on VLC Media Player) I couldn't move my mouse or anything so I realized that it froze. I restarted it and about 10 minutes later while watching videos on YouTube in full screen it froze again. It almost happened again after I restarted and tested it briefly, I full screened a video and my pc was lagging so I quickly pressed esc. I watched the video without full screen just fine.