I've done it !!!

this was the case:

I installed osx86 using iPC 10.5.6 Universal
didn't chose any kernel, and no video driver, only the rest
so it was running on 1024 res

i tried to use nvidia9000 series, but it didn't work at all.

then i installed NVinstaller v.52.pkg , and checked Vanilla and other drivers, and 512mb ofcourse
and i got QE/IC on reboot

but the resolution was still 1440x900

so i went to change it to 1680x1050 but it didnt work, only got the blue screen

next i did, i changed it to 1600x1200, and got the blue screen but restarted and it was running on that res.

then i did the same when i set it to 1680x1050, and it WORKED !!!

but, i still dont see any /library/extensions folder... which is weird


hope this helps many others