Well it was the G: on the OS previous to the reinstallion of Windows XP Pro. After that it changed to the D:, however was working fine until the installation of SP2, so I don't feel that it is a drive letter issue.
I did however do exactly what you stated to do, I changed my DVD drive letter to a higher unoccupied one and changed my slave hard drive as G:, as it was on the original installation of XP. This unfortunately made no difference and I have since changed it back to D:.
I used various apps, I tried GetDataBack for NTFS, EasyRecovery Professional and Stellar Phoenix NTFS. Only EasyRecovery Pro was an app which had cost anything, the other two being the unregistered versions. All pieces of software came up with slightly different results.
Stellar Phoenix showed a graphical representation of what was on the drive. (white being unoccupied, blue being data occupied, this was true for all three pieces of software) It showed almost no data on the drive, and recovered 150 megs of various gibberish files, starting with $ and varying in size significantly. Rougly 19 files I believe.
EasyRecovery and GetDataBack also had the graphical representations, however during the drive scan (which takes roughly three hours with each piece of software) the bar showed about half blue, half white, which is true. The 250G drive was roughly half full before this incident. However, once you proceed to show the data that is recoverable, it always shows 150 megs of these files, always the same ones.
The app you're refering to, "Recover my Files", is actually 69.95$, which I wouldn't have a problem paying if knew it was going to work. I am going to get the app, the full version, and I am going to try it. Wish me luck. The app I am refering to has the same name as the one you mentioned and I located here, http://www.recovermyfiles.com/