Whenever I try to play quake2 with a different engine (Quake2XP, Q2E, even aq2), my fps will drop back to 1 as soon as I shoot a weapon or else. When palying at, for example, outer base, I`m horribly lagging for like some seconds, then for some seconds it won`t lag, then it lags again.
Is there something I could do about it or my Intel HD Family graphics card is just sh*t?
However, problem happens in all kinds of resolutions, qualities, setups or else.
Anyway, my system is ->
2.00 GHZ
4GB RAM
Windows 7
32-bit
Graphics card is already mention.

Try applying this patch:

http://www.markshan.com/knightmare/down ... -win32.zip

Basically it's a fanmade patch intended to bugfix a lot of driver issues and make the game more stable. One of the major things it resolves is nVidia driver crashes when using OpenGL (and other graphical issues). Works perfectly with CoopOrDie, and it's not like a mod that changes the graphics or anything, it's basically just a patch for the standard game to improve stability and bugfix things, so the game looks like you're playing the vanilla one.

It also adds support for widescreen monitor resolutions if you want that.

http://www.markshan.com/knightmare/downloads.htm

Could you give us a bit more detailed information on your CPU? Besides 2.00 GHz, it should have a number of cores; additionally, is it an AMD or an Intel? (I guess it's an intel though since the video card also is an Intel)

Intel Pentium CPU B940.
64-bit operating system
Meanwhile, that patch seems pretty nice.