Hello
My computer is freezing and turning of screen randomly.
It seems like problem is with my GFX card.
When I use built in card it's all good.
Problems started after moving to another place. At first my computer wasn't used for about 4 months and then when I got it delivered to new place when I tried to run it SSD drive with windows on it died.
I bought a new SSD, installed everything and now it stalls.
Tried installing new GFX drivers, reinstalling windows and it's still doing it.
I have no idea what's wrong.
Might be PSU, motherboard or GPU.
But I think it's not mechanical damage because I can play BF3, LFS but it will freeze at some random moment.

Comp spec.

Processor Intel(R) Core(TM) i5-3450 CPU @ 3.10GHz
Manufacturer Intel
Speed 3.1 GHz
Number of Cores 4
Video Card 1 NVIDIA GeForce GTX 560
Manufacturer NVIDIA
Chipset GeForce GTX 560
Dedicated Memory 1.0 GB
Total Memory 4.0 GB
Video Card 2 Intel(R) HD Graphics
Manufacturer Intel
Chipset Intel(R) HD Graphics
Dedicated Memory 256 MB
Total Memory 1.7 GB
Memory 7.9 GB
Operating System Microsoft Windows 7 Professional Edition Service Pack 1 (build 7601), 64-bit
Service Pack 1
Size 64 Bit
Edition Professional
Display Maximum Resolution 1366 x 768
DVD TSSTcorp CDDVDW SH-222BB ATA Device
CD TSSTcorp CDDVDW SH-222BB ATA Device
Drive 1
Size 111.7 GB
Free 19.2 GB
Drive 2
Size 465.8 GB
Free 6.4 GB

the first thing i would try is to take out the graphics card and clean both the mainboard the card contacts.
it might have slipped a bit in there while moving.
do the same with the ram.
if that doesnt help make sure nothing is overheating (all fans clear of dust?).

did you play BF3 more than 1 hour? i mean it could be overheat cause damage on thermal pad / thermal pasta both on your proccessor or graphics card, or damage ram. check the speed of fan too, if the screen blinking maybe monitor refresh rate.

First of all thank you for your quick response
I did clean contacts on graphics but with what I do the same with motherboard?
There's no overheating, I've cleaned all fans and radiators.
Freeze can happen even after couple of seconds after starting windows even if computer was turned off for hours before.
Monitor is not blinking. It's just like a freeze of screen for a sec and than black screen.
Sometimes if it happens, music in youtube doesn't stop but still doesn't play next song in playlist.
Now i'm gonna clean ram connectors.

i meant the connectors on the mainboard where the card sits.
the best thing to do would be to lend a graphics card from a friend ort so to do testing...since its gonna be hard to find the cause if the stuff mentioned above doesnt help.

Yay!
I've cleaned RAM sticks and used second slot for gfx and now it's working!
But still gota clean up first slot and see if it's working in case I'll buy another card for SLI.
Thank you guys for help and hopefully see you on track when I get my wheel delivered here and it will be working

glad you got it back working.
race you soon