Slow computer after switching graphics cards (twice)

[onlinefreak5]

First things first, I know next to nothing about computers. I have a desktop that I used for schoolwork, running off an Nvidia Quadro K2200 for work. I also used it for games, but it wasn't a fantastic gaming card obviously. I graduated this past semester, and got an older Geforce GTX 750 TI (https://www.amazon.com/EVGA-GeForce-Display-Graphics-02G-P4-3757-KR/dp/B00J0ISHMQ) from a friend of mine. After plugging it in, with an additional 6-pin cable the previous card didn't need, and installing the newest drivers from the Nvidia website, my entire computer would freeze anywhere between 10 and 30 minutes after booting up. After trying to fix it for two days, I eventually said "**** it" and switched back to my old card. I uninstalled the new drivers and reinstalled the drivers that I had, but now the old card seems to barely function. I launched Overwatch and I can't even play it on low graphics settings. I tried a few other less intensive games (Borderlands 2 and Mount and Blade: Warband) and even those are both super laggy and choppy framerates.

Is there any reason the switch back would have messed up my OLD card? Because now I'm stuck with two different cards that don't work and my computer is practically non-functional.

End note: I don't know what information is needed to answer this question either, or how to find it. If you're able to help and there's a specific piece of info you need to do so, please let me know and tell me how to figure it out.

What I know off the top of my head is the two cards (First and Last the Quadro K2200 and the GTX 750 ti in between), running Windows 7. Almost nothing because I'm technologically inept.

Thanks in advance.

 

[bystander36]

It seems most likely that you messed up another component in your system in the process of switching video cards. It would help if you listed the system spec's, and you should monitor your CPU temps, clocks and GPU temps and clocks. Run 3dmark Timespy or Firestrike if you can, and post a link.

 

[Batmeat]

Sounds a lot like the card wasn't seated right or the power draw was to much, but we need the specs of your system to help. Cpu? Ram? Power supply? Motherboard and how many slots are used?