Well I've got an e machine t3072 and fried the processor because I broke the fan ,I have since replaced the processor and it did seem to boot

Them it went to dos and said non system disk blah blah blah

There are no beeps on start up
There is a built in graphics card

I have quite a number of replacement parts and have been working diligently with no success.

Was there something I missed?

If you get a prompt that says non system disk or disk error, then you know the CPU is working. That sounds like a hard drive problem. Go into the bios and make sure it's recognising the hard drive(s). You may have accidentally left an IDE cable or power cable off the hard drive when you put everything back together... I do that all the time.

Actually that sounds about right

But now it's doing that no signal bull
You I should probably talk that hard drive and re install everything??

Is it booting up at all before you get the no signal message? If it is, then it's probably drivers. If nothing come son the screen at all when you turn it on, most likely hardware related.

Yeah, I would probably reinstall everything if it can actually find the hard drive (if you can see it in the bios setup screen). That way, you rule out software as the cause, since it's the cheapest thing to replace (just takes a little bit of time).

You you git a bunch of other computers and I only got the one that works cause it's brand new

You I might even replace the hard drive just to make sure it's not that