I think I found the problem
there is must be some problem in my newer card
If I put on that card, whatever itself or both card system will be halt,get prolem and etc...
and forgive my poor english again...

I bought two different Voodoo2 Cards with a SLI Cable
One is 98's chip and 100MHz memory and the other is 99's chip and 110MHz memory
I don't know who made it because there's nothing like Diamond or Creative on card
At first I found I must install GLSetup first and upgrade driver to FastVoodoo or I Get an error massage say like "expected Voodoo2 none found" I don't remember it clearly,why?
and today I put on another card(I removed my USB Adapter) and Installed Drivers but I can't open Display Properties because it will be no response and System will halt when open any 3D programs like some demos,no blue screen, no illegal operation(maybe this in english),and no fatal errors,just halt at last screen...why?
at last forgive my poor english...