Slow starting up some things

Hi, I started to play a couple of games and I got some slowdown.
I was playing Shadowgate 64 when it started to show some major drop in FPS after I started a new game. Also in Aidyn Chronicles when you open up your menu(a scroll opens up) it lags up a bit to open. Also in WWF No Mercy the FPS is near 10-20, from the startup to choosing a match. How do you fix this?

I don't think it's my computer, by the way I have
Pentinum 4 CPU 2.00GHz
256 MB Ram

Also can this be the problem? This is from the DirectDraw6 Error.log

[5:38:28 PM 10/9/2002] Error 0x887601C2 - Error deleting zbuffer attachment

Thanks.
And nevermind about the WWF No Mercy, I accidently set the rendering device to RGB Emulation.