No signal from the PC to Monitor

This problem has been long term for me at the moment since I've been trouble shooting this issue for the last month or so to try and fix my PC. I assumed at first that it was my graphics card because my keyboard would light up and I could trigger the numlock on and off, which means the computer was booting, it just didn't have a signal to the monitor. So I searched through my things and found a spare card and popped it in and presto, the computer fired up. I did a few things on the PC, but noticed the screen would flash occasionally, which I assumed was an issue with drivers on the card. I didn't have the time to update the drivers before I left so I powered down the PC and was going to do it later. I come back to work on the PC and the same issue returned. All of the fans power up, the hard drive starts, but no boot screen and no signal to the monitor. This time, however, the numlock light would not light up on the keyboard and the lights never flashed on the keyboard. I tested the wire from the card to the monitor, which is still good and so I assumed, at this point, that my mobo has shorted out my graphics card.

However, upon further review of my old card, the fan appeared to be seizing up so it must have overheated and burnt out. My thoughts at this point now are that the card must have caused a short in the mobo, which in turn shorted out the other graphics card. The CPU is still good, as is the RAM, the HDD and DVD drive are also in good working order and the power supply is a brand new modular PS that I bought to replace my old one after it crapped out. I'm just looking for one of two things here: Validation on my solution to fix the PC or a solution to get me up and going which hopefully will either cost me nothing or less than a new mobo and graphics card