Chiahippo, I have a very similar setup as you. The only difference is I have a different brand hard drive, an Nvidia video card, and my Plextor 4824A is master and my PX716A is slave on IDE1.
I also have my 2500+ overclocked at 2100Mhz and have a Pioneer DVD-ROM as a slave drive on IDE0.
With 3 optical drives, they have not caused me any trouble. One thing I might recommend for you is to get at least BIOS 1008 for your motherboard. You will need to verify if the board is a 1.0x or 2.0 version. There are different BIOSes for each. The version number can be found inbetween the PCI slots near where it shows the mother board model A7N8X. This may not solve your problem but may help cure other issues.
My guess is it might be a driver issue or something with your video card. I know it might be drastic, but if you reinstalled Windows from scratch and it works fine, you might chalk it up to a bad video driver or some other kind of corruption that occurred in Windows.
You may want to head over to <a href="www.nforcershq.com">www.nforcershq.com</a> where they have an excellent Asus nforce2 motherboard help forum, you may get more assistance there...