I have someone who brought me a HP Touchscreen 310 all in one. When you power it up, the power button lights up and the fans come on but no video, it just stays black. I opened it up and cleaned it all out of dirt. Also tried clearing cmos, reset memory and cpu as well as checked all connectors... I have read that it is common for the cpu to go bad and also for the solder to act up on the video card. some people used the oven method to redo the solder on the video card. I am iffy on trying that being its not my computer. Is there anything i can do to narrow it down more? possible bad cpu, motherboard, video card? Any help would be great. It worked not long ago because i put a fresh copy of windows on it for them. It worked fine then.