Hi, my computer just started having some issues. It locks up when powering on at least 2 out of 3 attempts. When I do get it to power up, it ususally freezes within 15-20 minutes randomly. Sometimes while using internet, sometimes not. My AVG antivirus is not recognizing any issues, and I am ot sure what to do. All I know it is very annoying to have to restart computer every 20 minutes or so. Thanks!