Terminal illness of GPU/other hardware Maybe ?

I have a stupid question.

How can I check if my GPU is busy departing the good life. let me explain why I think it is the GPU.

Up until the weekend I have the most awesome experience with absolute stutterless setup setting with my new system 3770k. Saterday even made some FSX videos and then saterday evening I switched it off (by the way no software/drivers installed last 2 weeks - NADA nothing)

Sunday morning I got up and it was chaos with frames jumping from 2 to 30 to 50 to 5 to 1.. I have never seen this. Initially I thought it looked like a RAM issue (I have 2 stick of corsair 2400's in the new machine). Tested that by swapping them out and trying one at a time. All things stayed disastrous. i have cloned backup of my system that I made from 2 weeks ago after the last installed software of the new build. I then decided to use the clone HD as I thought something happened with my OS/FSX/Drivers. The result was the same ill effect. So that mean I can can eliminate the HD, the OS and the FSX install itself because ven 2 weeks ago the system was as perfect as I could have wished for.

SO that means it must be my hardware with old GPU (still gtx480) and the rest is basically 3 weeks old.

new motherboard - Asus ROG maximus v formula (said in a whisper)

new RAM - corsair vengeange 2400

new processor - 3770k

new CPu cooling - H100 corsair

New PSU Corsair

so the only thing that came out of my old system was the GPU so I suspect that to be the culprit. I thought I will replace the GPU in 3 months time, but it seems it is going to be sooner then later.

My question.

Is there any software/test I can perform that can indicate if the GPU is faulty. Living in South africa, not in a city, I dont have access to another card to test my system with another card. Now it is also a bit silly driving one weekend to a city and spending money to buy another highend card just to check if the GPU is indeed the culprit. I dont have a problem buying a new card but then at least I must be sure that it is indeed the instigator of the problems.

System work ok for like surfing the net, but I just cannot play FSX. (only simulator/game I have installed on my machine)

Any ideas please let me know how I can determine what is going on. I am open for any suggestion as this is killing me.!