The nVidia 210 has support for Windows 7 64 Bit, so Windows 7 is NOT your issue here.
Here is the specs on this card.
This card requires a minimum of 300 WATTS to function properly.
I see you have a 500 WATT PSU, I have helped other members who have had power supplies which were boarder-line with the requirements this card demands from the PSU.
The problem may and I mean may be that your PSU is NOT supplying enough AMPs to the card for it to function properly.
Also, SLI devices usually require a setting in the BIOS utility to function properly.
I suggest you enter your BIOS setup utility at boot-up and examine the menus for something related to SLI.
Check anything here in your BIOS related to graphics.
You may have a setting that is not set correctly for this card to function properly.
I will look for a owners manual for your motherboard to see if I can locate anything I can point out to you, which may be the reason your SLI type video card is sending messages to windows that it is not functioning properly and will let you know.
But you may need to look into whether your PSU is supplying enough to power up this card.