I have a desktop that was built originally by my cousin and I have changed some parts myself. I had upgraded the graphics card from a Nvidia gt 220 to an Nvidia gtx 960 and added a couple of sticks of ram. I had saved up and did a build for myself. My girlfriend offered to buy my gtx 960 from the old build since I bought another graphics card my personal build. I took the gtx 960 out and placed the gt 220 in the old build and then realized I needed to reinstall the drivers for the gt 220. Well when I put the gtx 960 back in and its not sending signal to the monitor. I tried a different monitor that used a port and still had no luck. After letting the psu sit turned off for a few minutes and gpu does not turn on. I turn the psu off then back on and the gpu turns on. The gtx 960 worked fine before I removed it.

My mother board is an ASUS M3A79-T Deluxe and it does not have an integrated graphics card so I cannot try to update drivers. My psu is an EVGA 600B.

I continued messing with the monitor and it analogizes that there is a signal but nothing shows up from the computer.