In response to my invisible hard drives that arent seen, thanks for the tips everyone who posted. a couple answers - the jumpers are set correctly, both the 160 and 300 have experienced this problem in slave set. only the 160 has been set in primary because it has an OS, the 300 does not, thus i havent primaried the 300. i have service pack 2 and the drives have already been formatted and i have data on them and stuff. and i am goign to download the new BIOS because i probably havent downloaded the new one since i bought my mobo. i'll re-post with an update!

thanks everyone for the help.

ASUS P4P800 Deluxe mobo
P4 2.6GHz Overclocked to 3.12GHz HT
2 GB Corsair RAM - 3200/DDR400
620GB Total HDD Memory
ATI Radeon X800XL 256MB
Plextor DVD Burner
Creative Sound Blaster Au

Are you installing things while being overclocked? If the PCI bus is being OCed you can have all kinds of issues. You should always revert back to stock settings while installing things.
I know, you have probably done this many times. The BIOS update probably isn't necessary. Also, you are responding to a different thread. If the thread is old and you feel you need to start over, at least refer back to the original one. I don't remember your exact problem and don't really feel like hunting for the original thread.

Below post is for reference.

http://www.computing.net/hardware/wwwboard/forum/44485.html

its ok. i set things back to stock, yes. but things seem to be working now, it just seems to be an odd on and off kinda thing, quite odd. and i didn't update my bios yet either, i dont really want to. we'll see what happens. i'll start up another post if my computer explodes. thanks everyone!

asus p4p800 deluxe mobo
2 gigs registered corsair ram - 3200/ddr400
2x 80 gb hdd
1x 160 gb hdd
ati radeon X800XL 256mb
420 watt antec
dvd-rw/cd rw/dvdrom
creative audigy something