Dell Dimension 4700 failures

Hello! This is my first post. I have come here for some assistance on one of my older Dell systems today, my first one. (I actually recently acquired another one). This was my first computer ever, a hand me down from my parents back in 2011. It never ran well... I've blamed it on many things over time, starting with the Pentium four processor aging, to bad caps on the motherboard, to hard drive errors. USB's not working, extremely slow performance, shutdowns, and weird/messed up POST codes at start up were all symptoms. Once I hit it once (not very hard) out of frustration, and it completely rebooted. Then, it worked fine for months. Just this weekend, however, I was reaching behind the unit to plug in a USB (the front USBs quit a long time ago, as I mentioned above), and it shut down without any signs of rebooting. I tried unplugging it for a while, and then plugging it back in (this worked in the past, it has happened before), but it didn't help. I checked inside, and the green LED on the motherboard was off. So, I began suspecting the PSU. A paperclip test confirmed my suspicion... and I could actually see the capacitors that failed inside upon further inspection. I tested the power supply that I though failed in my other 4700, and it was failed. I borrowed the working PSU from that computer and put it in the one with the failed PSU, but instead of booting it flashes an amber light by the power button. Did the power supply failure take the motherboard with it :(? Any help is appriciated! Thanks!

CryptoCracker

Is the power button LED, solid, or blinking and what is the colour?

What is the reading of the 4 diagnostic Lights on the back panel?

The Dimension 4700 Service Manual/Diagnostic Guides and Troubleshooter are here:

http://downloads.dell.com/Manuals/all-products/esuprt_desktop/esuprt_dimension_desktops/dimension-4700_service%20manual_en-us.pdf

 Are there any error messages, or 'Beeps'?

Yes, it is possible that the motherboard is shorted out [aka fried]

Bev.