2 Questions...

A friend of mine's computer was infected. I thought I would try to clean it with your help. However I noticed it was very dirty, the CPU heat sink completely blocked. Cleaned it up and no dice. Can't get to the BIOS, no hardware recognition. CPU or other components fried? Is it safe connecting the HD to my computer to retrieve files?
If so, how please.

 

If you are worried about virus contamination then you could put the HD in your computer and use a Live Linux CD to boot your computer and copy the files to a USB device. That would bypass any problems with infected files on your machine.

If you try to boot your friend's machine with no RAM installed to you get an error beep?

 

If you cant post it suggest a core component is not working. Most likely are Motherboard, CPU or PSU. Do you get any lights come on or fans spinning when you push the power button?

 

That is what I was thinking. After cleaning the tower I booted to see if the fans were working with nothing connected. The power supply starts the fans light, but no error beeps.

 

At the minute my money is on either motherboard or RAM. If you dont have spare parts to swap out and test with it could be difficult to prove which part is broken. If you have some spare RAM kicking around try that (If you have two memory modules installed try taking them out one at a time as the PC should noot with one good stick). If that doesn't work try disconnecting your components and remove them from the case. Place the MB on a soft non conductive surface such as card board. Insert CPU, RAM and GPU then try to boot. If you get to POST then it may be something shorting out your MB on your case. If it does not POST then our only option is to start swapping out components and test PSU with digital multimeter

Hope this helps and good luck

 

Thanks much, will start digging