They still sell floppy drives? Heh.
The only thing you did to the stock Dimension 5100 is change the PSU?
You obviously have power to the CD drive, because its opening and closing, so I don't see the PSU being the issue. All you did to the CD drive was unplug the power cable from it, and plug in the appropriate cable from the new PSU to the same spot, right?
These messages regarding "NTFS" and "PCI", could you elaborate on the content of the messages?
as suggested disabled it in the bios and SORTED.
What do you mean by that exactly?
If that's all you did, I don't see what happened, unless when you changed options in the BIOS you did something to affect the CD drive, as well. To my knowledge of motherboards that support IDE, the CD drive and floppy can be on the same IDE cable, and so maybe you took both out with that BIOS modification instead of just the floppy.