how can I know if my gpu is dead?

So I've been struggling with my GPU for about a year. Had to reinstall windows a lot because it went to black screen on login, and everything stopped working(i checked with the numlock key).
Recently no matter which version of windows or AMD driver I install, it goes to black screen the moment i'm installing the AMD driver (I tried installing through device manager or using the installer without ticking catalyst).
My question is, how would i know if the issue is actually with my GPU and not something else?
I've also been getting the error clock_watchdog_timeout a few times after installing the driver and waiting about 10 mins into the black screen.
I have the default i7 build and 5850m gpu.
edit: for more info, I've updated the bios and reapplied thermal paste to both gpu and cpu(after the blackscreen stopped going away).
also I'm using win8.1 64bit right now, but I couldnt get it to run on win7 64bit with the original dell driver.

 

This may not be the GPU. Could be the motherboard or another component (hard drive, RAM, CPU). First, try doing a power drain:

1- Remove AC Adapter
2- Remove battery
3- Hold down power button for ~20-30 seconds

Then from the boot menu (press F12 at Alienware startup screen), choose Hardware Diagnostics and let the test run in its entirety. Let us know how it goes.

 

aight i did as u said, ran the whole 30min test and no problems were detected.

 

So it works fine with Win8? Did you try other drivers in W7 besides the one's on Dell's site?

 

nope, the diagnostics were successful but I still cant install any drivers without it going into black screen and crashing.
I've tried the 15.7 and crimson beta, plus a few old ones i downloaded from guru3d, i get the same result for all of them.

 

Probably a hardware issue then. But it could be a problem with the CPU which can also indicate a problem with the motherboard itself. Have you tried re-seating the CPU and RAM modules? Do all CPU cores show up in task manager? The error you described seems to indicate a CPU issue:

https://msdn.microsoft.com/en-us/library/windows/hardware/ff557211(v=vs.85).aspx?tduid=(f25e91f13a92f2022f29d554614bce12)(256380)(2459594)(TnL5HPStwNw-Ejz0WfBcuM4_rojlWwOCDQ)()

EDIT: Also, are you running the latest A09 BIOS?

EDIT 2: I also recommend running a hard drive diagnostic test. What model hard drive are you using? Also make sure you are monitoring your temps on the CPU and GPU. Make sure they are not overheating.

 

I've seen this quite a few times on many different (not only Alienware) systems. I'm 99% positive it's the video card.

 

I'll try reseating them once I get back from work.
Task manager shows everything normal in regards to CPU, all cores and processors are fine.
I use HWMonitor to check the temps, theyre aruond 60-70c which is normal for me. But it doesn't show any GPU, i'm guessing it's because I haven't installed the GPU drivers, so its detecting the Microsoft display adapter.

Yep
[/QUOTE]EDIT 2: I also recommend running a hard drive diagnostic test. What model hard drive are you using? Also make sure you are monitoring your temps on the CPU and GPU. Make sure they are not overheating.[/QUOTE]
i'm using an OCZ agility 2 ssd, but i tried my original hard drive and tried both win8 and 7 on it, same problem

 

I was almost sure it was the video card too, but the watchdog timeout error is related to CPU, that's why I need to know for sure if it's the GPU so i can replace it. Well...hopefully, doubt there will be any parts to be found here in Malaysia

 

Since you did all those tests, I'd echo Porras's post about the video card failing.
That's most likely it, but it doesn't exclude a failing motherboard either.
CPUs themselves rarely fail, but that's a possibility too. It's gonna be hard to diagnose this without trying replacement parts.

Do you know anyone who can loan you a video card to test? And try installing drivers for the graphics card to check its temps.