Need Help : PC crashing Frequently from past 1 month.

Hi all,
I ran into this issue this month. My PC is crashing almost every time i use some GPU intensive work.
1. When i launch a game the system crashes without any BSOD or Memory Dump. I have already checked that the memory dumps are enabled but those are not written to the Mini dumps folder.
2. i Tried running Furmark the test crashes the system as soon as i click on test on user defaults.
3. All the components were working fine until last month and there are no hardware upgrades done since.
4. I have tried a lot of things without any success
a. I have reinstalled every ting for like 4 times still the issue persists.
b. I monitored my CPU as well as GPU temps they are at mat around 45 deg Celsius.
c. i have updated all the drivers to the latest without any success.
d. Have run Memtest86+ also all passed without a fault.
5. I think i am out of ideas from my side. I have read all the forums for this issue but didn't got a solution that fits me. Please ny kind of help will be useful.
6. I think its a GPU issue or some GPU driver issue as it does not happens when normal computation watching HD videos and all but as soon as i run a game or do some GPU tests it crashes. Please Help Guys.

An Update now it crashes without any load also i wasnt doing anything other then writing this post and it crashed again. I am frstrated with this Please help.