Problem - Not Sure of Cause?

[daniel101191]

Ok so I built a new rig about a month ago, and have just got 3 monitors for christmas. Problem is they all worked fine to start with but then not long after, it froze up I had a blue screen about the display adapter not functioning correctly, and I couldnt use the computer because It just froze up on the desktop as soon as it started, Well i turned it on the next day with just one monitor in and it worked, so I tried it again and now it worked for about 10 minutes and one of the monitors all of a sudden went off (as in no signal) then 5 minutes later the other side went of, and I was just left with the middle.

Setup:

EVGA GTX 660 SuperClocked 2GB GDDR5 Dual DVI HDMI DisplayPort PCI-E

Intel Core i5 3570K 3.4GHz Socket 1155 6MB Cache Retail Boxed Processor

Crucial 8GB (2x4GB) DDR3 1600Mhz Ballistix Sport Memory Kit CL9 (9-9-9-24) 1.5V

Coolermaster Elite Power 500W PSU 253900

Asus P8Z77-V LX Socket 1155 VGA DVI HDMI 8 Channel Audio ATX Motherboard


The monitors are all VGA 19" 1366x768 , so i had to buy £10 adapters off ebay to convert the signal to HDMI and another one Display Port, now surely it cant be these?

I am about to RMA the graphics card but have no idea what else it could be its doing my head in! I read a similar problem with 660 series people are having , should I have just gone for eyefinity card?

Thanks for taking the time to read! any help appreciated