So those of you who checked out my thread a few days back may remember that I inquired about whether my PC was up to snuff to support a GTX 980 without bottlenecking somewhere, and you gave me the go ahead that my system was fine for an upgrade, but now I am back with a far bigger problem.

I took the PC and the GPU to get it fitted at a local PC clinic store and after paying a small fee, I returned home to find a problem: the PC wasn't working properly anymore. First came a beep that occured every 20 seconds or so in a minute timeframe on the HP splash screen. It should be noted that I was unable to access the BIOS as it would not respond to keyboard/mouse inputs. After that, it would hang on a blank screen with a flashing typing cursor and would not progress. So I kept turning it on and off, but the problem persisted, leading me to search the web and find out that a single beep indicates a GPU problem.

Going off this assumption, I took it back to the place to see what could be done, and the person who worked there said he had tested it with some of his own spare GPUs and the system was booting fine. Cue the next day, where I assume that the 980 was somehow faulty and ask to have my old 680 fitted back in as so I can have a working computer again, but here's the kicker: now no graphics cards would work, and to top it off, the problem had worsened.

The PC would no longer even display anymore and would proceed to shut off after 30 or so seconds, before quickly restarting. This happens over and over unless a GPU is not present, in which case there is still no signal of course but this automatic shut off would only occur once and then the PC would proceed to stay on. I've been receiving mixed advice from the "experts" I've been troubleshooting with; one claims it is likely a PSU problem whilst another suggests the motherboard is damaged. All I know is that my PC was working fine up until I handed it over to have the 980 fitted and each subsequent visit to this place has only worsened my PC's condition.

Once again, my specs are as follows:

CPU: Intel i7 Quad-core 3770 @3.40GHz

GPU: Nvidia EVGA GeForce GTX 680 (with a 980 fitted retroactively)

PSU: Silverstone 1000w st1000-p strider

RAM: 12GB

OS: Windows 7 Home Premium 64-bit

I would say that the most likely cause is that your GPU is not receiving sufficient power. That could either be due to a connector being incorrectly installed or a PSU problem. I would suggest plugging your computer in through the built in video connectors and see if it displays then.

@the_devoid: PC doesn't display even when connected to the built-in graphics.

Sounds like a PSU problem. I'm curious to know what type of PSU that is and how old it is.

@jclane: Also would recommend if possible to list the model number and make of your motherboard. The BIOS Beep codes are different depending on the make of your mobo. Though you might of known that and totally be right about the issue being related to your graphics card.

Other then that only thing I can recommend is checking each computer component one at a time making sure it's connected properly.

I recently installed a new psu on my system and ran into the bios beeps. I got it working cause I didn't have one of the mobo power connectors in all the way. Sometimes it just takes another look at to see if everything is properly seated and connected properly.

@mb: I'd have to get the box out of the attic to get brand and model info, but as for age, my old PSU completely died so I ended up getting it replaced about 2-3 months ago, so I've had this new one for that span of time.

I would suggest unplugging and replugging in the power connectors for your motherboard. Especially if is that new it might have come lose when the GPUs were being swapped.

OK, I checked back on my purchase history from the place I got the PSU from and have updated the OP with the name and model.

@jclane I'd do this. Make sure all those PSU connectors are in properly, on both ends. It's easy to forget those things or jar something loose either during an upgrade or when moving cables around, or even when transporting the PC to and from the shop.

Common culprits are: the CPU aux power connector on the motherboard not being connected at all, one of the PCIE connectors on the GPU not being connected properly or at all or loose, or having not enough PCIE power connectors hooked up to the GPU or not the correct type. Also check the connections on the PSU side since the one you have is fully modular.

I think the GTX 980 requires two 8-pin PCIE power connectors and the 680 is probably two 6-pin...if I were looking at your rig right now that would be the first thing I checked.

So I got it to display and boot correctly with the 680 but now I am getting an error message on startup about no boot disk detected or the disk has failed.

Make sure hard drive is first in boot order in BIOS. If still not booting or doesnt show up make sure power and data connections are secure for the hard drive.