nvidia 7900gs settings problem ...

can someone help? im having some problems with my comp. ive had it for just over a week and naturally i had the whole problem with cineplayer thing where it wouldnt play dvds at all. i got that fixed with the patch and everything but now that the dvds play ive encountered a different problem: the brightness/contrast settings are wrong. ive used the nvidia control panel to change the settings, while playing a dvd of course so that i could make sure to get it right, but i cant get it right for all the programs. ive got media center, cineplayer and media player to watch dvds but if i get the settings right for media center/player, cineplayer shows the dvds too dark and if i brighten it up media center/player shows them too bright.

 

and then theres another problem, if i go into media player and go to options > performance > video acceleration > advanced > and in the dvd video area, select the use video mixing renderer check box, that allows me to capture images. when i do that though it brightens the picture up more and i then change the setting to darken it but everytime i restart the comp and go into media player everything ive just said goes back to normal - the use video mixing renderer check box unticks and everything, and redoing it everytime i want to watch a dvd is annoying. whats the problem and how can i fix it?

 

for the record my other comp specs are:

 

Intel Viiv Core 2 Duo E6600 (2.4GHz, 1066Mhz, 4Mb)
2048Mb Dual Channel DDR2 533MHz (2x1024Mb) memory
320Gb Serial ATA Raid 0 Stripe (2x160Gb 7200rpm drives with Databurst cache)
256Mb nVidia GeForce 7900GS graphics card
Intergrated Sound Blaster Audigy ADVANCED HD software
16x DVD +/- RW
16x IDE DVD ROM drive
1.44Mb floppy drive
Internal 13-in-1 media card reader
56k V92 modem
Microsoft Windows XP Media Center Edition 2005

 

thanks for your help :-)