extreme lag with newer games

[roll]

Hello. I am having lag issues, despite my decent PC (Athlon 64X2, Dual Core, 2 GB ram, Nvidia 8400 GS).
The first time I noticed this was with "Frank the Farmhand", it was very very laggy (music, movement and mouse movement). The PC was on all day (the strange thing is that this somehow influences the game's performance, my other software don't seem affected but with this game, if I play it just after turning on the PC only the music lags, while if I start the game during the evening, the whole game lags). Then I noticed this with "Cayanne Pepper" and "Cosmos Quest". I don't have problems when playing old games designed in 320x240 in 640x480 mode.

Oh and by the way, filters doesn't solve the problem.

edit 2: Zelda Dance Remix 2 also lags like this.

[Layabout]

OS? Anitivirus? Windowed or full screen?

[roll]

Windows XP SP3, fullscreen.

Now that I just turned on the PC, all these games run smooth. It's still strange that AGS games are the only programs affected by lag when I have been using the PC for a couple of hours.

[Pumaman]

Do you get the problem if you run the games in a window? Next time you get the problem, can you try temporarily disabling any anti-virus app that you have running and see if that helps -- sometimes they decide to start a scan which can slow things down (though why this would only affect AGS games, I don't know).