well, there's one problem. you aren't going to get shit running with the intel 810e (i'm assuming that's what you're running). i used that, and it doesn't do crap for n64 emulation. Jabo's D3D6 1.5, which is included with Project64 1.5 like Clements said, should do it. i'm not sure what your deal about "Direct3D6
not 6 1.5" meant.
Most plugins require the use of the graphics card for aceleration. I know that I used to use an Intel 82810E onboard graphics, it worked, but it was really choppy. I recommend that if you wanna play Smash Brothers, get a 64MB graphics card, make sure you know if you have an AGP interface or not. Have a Processor about 1 Ghz if you use 1964, and if you wanna use Project 64, have a 1.2 Ghz processor.
Too cheap to buy a graphics card, try using TR64 OGL, it might work, but as I said, its choppy with onboard graphics