Thanks to all 
but i fixed the problem with another trick...
I only overwrited the file C:\WINNT\system32\kstvtune.ax with a version a friend send me (thx to him) after booting in Secure Mode.
After rebooting Win2000 the "3dfx TV" worked *jipiiieee* !!!
But there was a problem with the frequencies... had to set each channel 1MHz down.
Now everything works fine but i think the TV-quality is not that good than in Win98
- don't know why.

but i fixed the problem with another trick...
I only overwrited the file C:\WINNT\system32\kstvtune.ax with a version a friend send me (thx to him) after booting in Secure Mode.
After rebooting Win2000 the "3dfx TV" worked *jipiiieee* !!!
But there was a problem with the frequencies... had to set each channel 1MHz down.
Now everything works fine but i think the TV-quality is not that good than in Win98
