Computer Upgrades

I have a home-built computer, an Asus mother board, with slots for more than one video card. I have an Envida gforce 7500, Windows XP(x64), and a 250 gig hard disk. Here are my thoughts, and questions:
1) Get a normal version of windows Xp(pro with out OEM) I was told to get with out OEM, but im not really sure what it means, or does, can some one lighten me on what it does.
2) I want to get a 120 gig hard disk, use my Xp(x64) as a back up, and storage, with removable hard disks.
3) I want to get another video card, my mother board does have the slots, but i am not sure if i have to get the same kind of cards, as in, 2 gforce 7500, or one 7500, and another 9400, and they would both work.

~vista will not work, not for the programs i use mainly~

 

1) I think whoever told you to get a "non-OEM" version of Windows was referring to a non-branded version, meaning that you wouldn't want one from Dell or HP. Personally, I think you should stick with the x64 Windows as it has the ability to use MUCH more memory, and everything in the future is going to be 64bit.
2) You'll need to explain this a bit more clearly 'cuz I'm not 100% sure what you're talking about, but with SATA (and IDE) hard drives being so cheap these days a 120gb is a waste of money when you consider that a 250 or 320gb is not too much more than a measly 120gb.
3) With SLI, you must have both cards the same; meaning that you cannot add a 9400 to a 7500. You'd be better off dumping the 7500 and getting a single nVidia 9600GT. They're pretty cheap right now (as are the 9800/250 series). You'd get better performance from a single 9600 than you would from two 7500s (or even two 9400s).

I hope this helps! :-D

[dlb]
:major

 

The reason i want to get away from XP(x64) is I keep running in to programs that work on every normal version of xp i run it on, but they dont work on mine. If you know something like an emulator, can you point it out to me, and i do apologize if you have one on your site, and i missed it.