I'm not certain if this has been brought up before, but I thought I should go ahead and discuss this. My roommate accidentally shut her computer off during a Windows update, and now it will not even power back on. There is power still going to the PC power supply, indicated by the the green light near the plug receptacle. I am uncertain how to recover her computer from this, since it will not power on even to run the recovery disc. It is an HP Pavilion Slimline 400 with Windows 8.1. Any suggestions will be quite helpful. Thanks.