Hello there.I've been a fan of this site for quite some time and have gotten some problems resolved just by searching the forums. However my computer has recently developed a serious problem that I haven't been able to find a fix for. It goes a little something like this: Issue #1- On our shared desktop a family member will try to log into his/her account and after a few seconds of loading settings the screen will go black and only the white cursor is visible.Task manager can't be launched and no keyboard shortcuts will respond.It will remain this way until manually turned off.Sometimes it will allow someone to log on and access the internet after being booted up again but most often the screen will go black again after 5-10 minutes. Issue #2- If it happens to be a good day and issue #1 hasn't occurred yet someone might be able to watch a few videos or play a game for a short time then suddenly everything will go black and the tower makes the sound it does when it restarts. But instead of restarting once again there is only a black screen this time without a moveable cursor and the fans can still be heard running. We've had this computer for about 5 years with numerous common,and usually easy to solve,problems but this is leaving me clueless.Automatic restart has been disabled,full virus scan found nothing,no new hardware or software has been installed recently and no other intentional changes have been made. I'm not sure what specs or other information to list here but any help would be greatly appreciated.