I recently Installed and tried to play Janes Usaf on Windows 7 but i'm having some problems the game is lagging and in the option menu Trilinear Filtering, Objects Mip-Map and Terrain Multitexture are grayed out.
My Specs are:
Windows 7 Home basics 32bit
Amd Athlon II X2 260 3.2 GHz
4gb ram, 3gb usable
Ati radeon hd series 5750 1gb ram

Hier is a link to a Clip that shows my Problem!

Youtube

I can't help you, but that clip reminds me what a fine looking game that was.

From that, it appears that your rig is having trouble with the DX7 graphics of the day and this is a big problem since IIRC, there is no Glide option.

While for DOS and Windows Glide games, we are well served with emulators and wrappers, I haven't seen anything that can wrap pre-DX9 games to a form that they can be expected to work with a modern graphics driver.

What 'someone' needs to do is create a proxy DX7 dll (maybe based on code from the open source WINE project) that takes the incoming DX7 commands and repackages them to DX9/10/11 or OpenGL2/3/4 commands.

This may not be significant, but a review at the time indicated that the game was having trouble with AMD CPUs:
http://www.combatsim.com/memb123/htm/nov99/usaf-rev1.htm

Never mind! I've dug out my old Pc and installed Windows 98SE on it.

I'm impressed you even got it to run. I think the last time I managed to make it work was under XP, and even then the quick mission builder part of it was cocked up due to some issue with the dropdowns on it not working on anything newer than Windows 98.

As for the supposed issues it had with AMD chips back in the day, it ran fine as I recall (I used AMD back then) but there was some extra mode that supported an Intel-only CPU optimisation. I don't remember it being meant to make any major difference though.

Maybe give D3DWindower a try.

download link