Question PC is on but monitor is sleeping

[Daksterinho]

So after my GT 630 Gpu died I plugged the VGA cable into the motherboard for integrated graphics. Kinda unexpected but hey, it was an old Gpu and it wasn't great. The integrated graphics worked and everything was smooth, until I opened the case to see if everything was in order, which it was. Then I plugged my PC back in and it booted up normally, and after 20 minutes it crashed. 2 more boots and it doesn't even get to the motherboard boot visual. So I opened it once more and took out the RAM, CPU and unplugged the 2 hard drives and 1 SSD. After applying new thermal paste thinking overheating was the issue, assembling the components back together and plugging back in, it booted 2 times and the 3rd time it stayed on but the monitor is sleeping, almost like there is no signal. Any tips on how to fix this problem? My Specs are: I5 4440, 8GB DDR3 RAM, old and cheap PSU (might be the problem). Any help is appreciated!

 

[Daksterinho]

Update: the mouse isn't working either, so it's probably the PSU