DVD drive recognised by Windows XP, not BIOS

Hey,
I can't tell if it is a driver problem but maybe you can point me in the right direction.
I have a Fujitsu Lifebook s6231 Laptop and a few months ago the computer would take 20 minutes to boot. The DVD drive has a quick-release and one day I found that the computer would boot fine if the DVD drive was disconnected from the computer. I figured replace the drive and all will be well.
My old drive was a UJ-830B (a slim drive) and I tried replacing it with a UJ-831B. When it came in the mail the drives looked identical, just move the harness and install!
The drive installed perfectly! sooooo easy, the driver loaded right from the drive and everything. I was playing dvds within minutes! but........
The next time I turned the computer on the drive didn't show in "My Computer" or even the device manager. I did a lot of reading and found that it wouldn't be compatible if it wasn't recognized in the bios so I checked that. No cd rom in the bios!!!!
It worked though, so I was confused. Remembering my old problem I started the computer without the drive connected. Then after Windows completely loaded I connected the DVD rom again. IT WAS THERE!
Confused, I called the company who sold me the drive, he had never heard of my problem. He asked what the drive firmware was, it is 1.00 and so he asked me to send it back and he would replace it with one that had newer firmware. I did
Same problem with now the UJ-840. If I want to use the DVD drive I need to wait until Windows XP boots completely and then connect the drive. BIOS still doesn't recognise the drive, I am sooo confused.
I have looked for firmware updates for my Fujitsu s6231 Laptop and found no new updates.
Are there any suggestions you might have? Any forums I might have better luck asking? Is it a driver or firmware issue?
OH! one last thing
the old drive UJ-831B still WORKS!!. I used it to reinstall windows during all of this! The drive is just really old, makes a LOT of noise and makes my computer take forever to boot.
I appreciate any advice!