Hello,
I just installed a fresh copy of debian on my computer. I have 2 physical hard drives: one of 20GB running linux and swap (hda1/hda2) and one of 120GB with one fullsize fat32 partition (just changed to linux). linux does not even detect the 2nd drive although my BIOS setting are OK (i think).

by the way, how do I mount an USB drive?? (is connected and recognized in system monitor)

thanks for replies, R5d

How do you know this?
Try this as root:
fdisk /dev/hdb
And see what the output is, the partition will most probably be /dev/hdb1.
You need to create a mountpoint (e.g. /media/win) and then you can mount the partition to the mountpoint with
mount -t vfat /dev/hdb1 /media/win
You might need to edit your fstab file before being able to mount the partition, I don't think you have to but I'm not sure anymore.

Anyway, you can add this line to your /etc/fstab file and save it
/dev/hdb1 /mnt/d vfat user,rw,exec 0 0

For the usb drive you can do something similar, I just wrote a kind of howto for that to help out some buddies so I'm gonna direct you to this page instead of re-writing all that stuff.