Took my GPU Out and Put it Back in and Computer Doesn't Turn on Anymore

[G Bell]

So I was gonna sell my old HD 7950 to a friend for 70 bucks and I thought I better test it so see if it worked first. When I put it in it seemed to work so I turned the computer off and stuck my current GPU (R9 380X, I know it's not really an upgrade but it's a long story) and the computer just straight up didn't turn on. Literally nothing happened except the noise of it attempting to turn on (the fans were completely idle). It just sat there. So I plugged the monitor into the onboard graphics, and again, nothing happened. Then I decided to try my old GPU and it worked. At least that's what I thought... When I played CS:GO I got horrible stuttering all over the place no matter the settings, which did not occur when I used to use it.

I've had a problem with this computer before where it would perform terribly before I restarted the computer several times, basically a lottery. It would always take ages to boot up if it was still being slow as well. So I replaced the power supply, nope. I replaced the GPU, nope. I replaced the motherboard, finally the problem was fixed. Dodgy PCIe slot apparently, I think I broke it as after a few weeks of building the computer it started playing up and then I realised I had the graphics card seated improperly.

Computer Specs:
CPU: Intel Core i5 4460
GPU: Asus Strix Radeon R9 380X/ Sapphire Dual X HD 7950
MoBo: MSI H97M G43
RAM: Kingston HyperX Fury 2x4GB
HDD: Seagate Barracuda 1TB
Case: Silverstone PS08B
OS: Windows 8.1
DVD Drive: Samsung something or rather

I'm worried it's the motherboard again (I have no idea what I did this time, the only thing I can think of was that I accidentally dropped the GPU onto the motherboard once or twice but that was from like 10cm really shouldn't have killed either component. If so, so much for military grade MSI...) and I'm honestly on the verge of giving up on this computer and just getting a console.

 

[bajgur]

try reset/clear CMOS.
any beeping sound?

 

[Dustybin]

Firstly with the stuttering in CS:GO did you remember to connect your monitor to the 7950 or did you leave it connected to the onboard? If you were using the iGPU of the i5 then that would explain the performance. You should if you want to make sure things are fine with the 7950 install DDU and then clean reinstall all the drivers.

With your R9 380X are you sure you had it correctly seated in the PCIe slot and did you definitely connect all the PSU cables back into the card? Did you need to disconnect anything from the motherboard to get the card working? You might have damaged your card taking it out (especially if you dropped it into the case) a PCB can easily come to harm if you're not careful. If you get no display with the R9 380X even after checking all the cabling etc then it has probably come to some harm, ask your friend to check it in his PC as a final test and if that fails you're probably going to be looking at returning the card if you can, or cutting your losses.

 

[G Bell]

The card was definitely connected and seated properly. I don't think it would have been damaged as it has a back plate. As for with the 7950 it was definitely plugged into the monitor. I remember plugging the HDMI cable into the onboard graphics and then realising and switching ports to the 7950's HDMI. I tried DDU and then reinstalled drivers. Still the same stutter. One thing I noticed was that the first time I attempted to reinstall my drivers AMD's autodetect detected my card as a Firepro card for some reason, which can't be good. I'll try the R9 380X and resetting the CMOS tomorrow.

 

[G Bell]

Ok, so I put my new GPU back in after resetting the CMOS and then when I was plugging the connector in I suddenly went: "Hey, the connector slides in much easier this way..." So yeah... I plugged the connectors in the wrong way. The computer has booted now but because I cleared the CMOS I have to do the "Load optimized defaults" thing but I can't find where that is.

Edit: So I worked out the BIOS, uninstalled the old drivers and reinstalled the new ones and it works now. Thanks so much for your help guys!