Ok, This is driving me nuts!
I have a 200GB Western Digital IDE hard drive. Originally I had it mounted on a ix86 Slackware machine. For kicks and giggles I tried putting the hard drive on my ix86 NetBSD machine (incidentally I use it as my router). At any rate, when I put the hard drive back onto my slackware machine it would cause the boot process to hang up at

Partition check:
hda: hda1 hda2
hdb:

and nothing else (I have let it sit overnight)

I brought the disk back to my BDS machine and noticed that it didn't have a disklabel any more (if it had one at all). so I used what the BSD kernel thought the label should be to write one back onto the disk. That didn't fix it.

At this point I'm willing to loose the data on the disk, I just want it usable on my linux machine.

Does linux use disklabels just as BSD does? or does linux use something else to mark partitions? I have been unable to find any mention of them in the linux man pages

is there any way to "Kick" the boot process to at least get the machine to boot the the hard drive attached?

And does anyone know what precisely caused the problem in the first place?

Don't know much about BSD, but doesn't it use a completely different filesystem? You may have to do mkfs.ext3 or mkfs.reiserfs on it for Slackware to detect it. What does cfdisk show? What is in your /etc/fstab file?

thats the problem...... It wont finish booting. it stops and is looking for something it never finds so it just sits there.

Assuming that hda is fine and has your distro on it, try removing the hdb drive (which you use for data?). Take a look at your fstab; how are you mounting the hdb drive? Which filesystem is it supposed to be?

I strongly suspect that BSD formatted the drive with a filesystem that is incompatible with Slackware. You might want to ask this question in the BSD forum.