I Need Help after Upgrading from Windows 98SE to XP!!!

Greetings! I am a newbie to this forum, - I need serious help in recovering lost data!
Okay- I have a basic home studio that I use to record. I have two computers in there- one to record (my old workhorse that I have lost data after the upgrade) and my mastering computer that has XP loaded on it.
The workhorse had Windows 98SE loaded on it and the software we use is Magix Studio Deluxe by Samplitude- I have three hard drives on the Workhorse- My primary (c) a slave (D) and also a removable drive(F). I have been putting off upgrading to XP because the workhorse did so well- but I finally gave in and did it- I upgraded (and the trouble began!)- Prior to the upgrade I thought I transferred all of my data to the Mastering computer- What I actually did was copied my C drive from the workhorse to the Mastering computer- After the upgrade my workhorse has serious issues- I updated all of the drivers and now the computer will lock up and freeze with no warnings- I have put another fan in thinking the freezing was a result of overheating. I have the majority of our songs were placed on the C drive- but there are a few that were placed on the secondary drive. After I did the upgrade, I didn't check the secondary drives. Last night I went to bring up a song that was stored on the D drive- My computer sees the other drives, but when I go to open it it says "Drive D is not formatted - Do you wish to format?" I don't want to format the drive- because I will lose all of the data-
Does anybody have any suggestions to what I can do? I am really in a panic! I have thought about uninstalling Windows XP and reverting back to 98SE? I am really worried about this- Any help and or guidance is always appreciated! Sorry for the length! Please give me guidance!