Desktop Hardware and Upgrade Questions

So i have a 7 year old HP Compaq 6200 Pro MT that i use for school and web browsing and it really hasn't bothered me much until now.

I have a Nvidia 210 pretty edited** i know, but gets the job done for what i want the PC for, but yesterday i decided to remove it and use the onboard graphics instead, so i enabled the igpu in the Bios and removed the Gpu, when all was done i plugged the monitor in to the motherboard VGA slot and started the PC, the monitor went to power save Mode and the monitor light turned orange and my keyboard wouln't light up aswell, altough my mouse did.

What i did next was reinstall the 210 and plug the VGA cable in it, and when i started my PC it kept displaying the power save message and going blank and the keyboard wouldn't light up aswell.

My front leds turn on, the CD Drive is working it opens and closes, the fans spin, and if i leave the PC on for about a minute they start going crazy loud, this didn't happen before.

I have removed the Cmos battery and put it back in the PC

I have reseated the Gpu

I have Reseated the RAM modules and tried botting with just 1 RAM stick

I have reseated the Cpu

Nothing as worked so far..

Im starting to think maybe the psu is going bad, if i remove all the RAM my MB beeps like it should, but if the psu was bad the fans wouldn't work along with the CD Drive right?

Edited**