graphic card problems

[jeppe005]

So ever since i've gotten this computer i've been using a HDMI cable to connect to the TV from my acer predator computer. So one day i was starting my computer and on my TV it said No signal. first i thought it was my HDMI cable but i tryed to connect my ps3 to the same tv with same HDMI cable and it worked. so i connected my computer to the TV with a so called RGB cable and it started working and then i started Dark souls and got "Dark souls prepare to die edition executable has stopped working" and i tryed on different games and none worked so i figured something most be wrong with the graphic card but im not so good with computers in general. Help would be approtioated. i got an NVIDIA GeForce GT645 up to 4095MB if its important to know

 

[jeppe005]

please help :S?

 

[potpolima]

scan for virus
update driver and windows
fix registry errors
disable useless services that might cause errors to your pc

 

[jeppe005]

help please 😛?