computer won't fire up

Do you own the work computer? If not don't mess around and send it into the IT team where she works.

If you own it, I would pull all hdd's, floppy's, CD/DVD drives, video cards and memory. Boot the machine. If it beeps at you, power down and add the video card. If it still beeps at you, power down, and add them memory. Repeat with each device until it faults. If it doesn't work with everything pulled out, and you have swapped out the powersupply, it is the CPU or the motherboard.

tech support is for?

Ok, now it is likely that something is loose or has a bad connection. Or, you hosed the system.
Make sure that the RAM is inserted all of the way -- sometimes it seems like it but it is not, and this will bring the problem mentioned.
Also, make sure that the RAM is the right RAM for the system, or the same thing may happen.

But you might be lucky...
Try this:
Take out the processor and the video card.
Replace the processor and apply a very small amount of thermal paste then replace the heatsink and fan. Now boot up, you should hear the computer give out a sound. This sound indicates that there is no video card. Now replace the video card and boot up. Hopefully your system should now boot up correctly. If not replace with another motherboard. Hope all works out for you.

You may have transfered some ESD (Electric Static Discaharge)to your motherboard causing permanente damage.

Noting all the recovery steps you have tried, I would look at getting a new mobo next.

I know your pain!