Video Card and Command and Conquer

I run dual monitors from one graphics card. When i am playing Command and Conquer I play on one monitor and i can display different things on the other monitor. If i want to manipulate anything on the 2nd monitor i must minimize the game and then i am free to manuever on the other monitor. The only problem is that it causes network issues. My question is - I am building a new computer and i was thinking about getting 2 seperate Video cards in the hopes that i can run other applications independently from Command and Conquer by having C&C just using one card. I was looking at getting the XFX GeForce Black Edition. I will probably run Vista 64bit and currently running XP media Center. I have also tried adding -win to the shortcut command line but then i dont get the full screen.
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4296573&CatId=3585

 

Windows limits you so that if you have a full screen application you cannot access the other screen. No amount of graphics cards will change this.

 

what would be the use of Two Video Cards. I guess 4 monitors?

 

Yes, or SLI or CrossFire.

 

whats the difference between SLI and crossfire. I guess i need to ge research these.

 

SLI: nVIDIA's method of using 2 cards in tandem. This method requires a bridge chip that is supplied with the motherboard

CrossFire: ATI's method of using 2 cards in tandem. This is run through the PCI-E interface.