|"Why would my DVD burner all of a sudden remove itself?"|
Because it is defective and can't reliably achieve it's 1X speed, often because the motor bearings are failing, or there is a problem with it's data cable, or with recent DVD drives, possibly because you are using the wrong data cable type, or a lot less commonly it's logic board has failed, or a laser or laser circuit has failed (burner drives have at least two lasers),
OR - there is a known problem of XP occaisionally "losing" an optical drive.
If the DVD drive is capable of 16X DVD +R or DVD -R, or greater, if it is IDE connected it requires an 80 wire data cable in order to be able to achieve it's fastest speeds. If you use a 40 wire data cable it will probably still work, but you are likely to get data errors when you try to use it at it's faster burning speeds, or it's possible you will get data errors in other situations.
40 wire data cables are fine for any optical drive with lesser specs, if only optical drives are connected to it - if there is a hard drive on the same cable, the data cable has to be 80 wire to support the hard drive's UDMA66 or greater, unless the drive is really old (e.g. 1999 or older).
It is common to un-intentionally damage IDE data cables, especially while removing them - the 80 wire ones are more fragile. What usually happens is the cable is ripped at either edge and the wires there are either damaged or severed, often right at a connector or under it's cable clamp there, where it's hard to see - if a wire is severed but it's ends are touching, the connection is intermittant or not up to par, and you will randomly get data errors.
Another common thing is for the data cable to be separated from the connector contacts a bit after you have removed a cable - that can cause intermittant data errors - there should be no gap between the data cable and the connector - if there is press the cable against the connector to eliminate the gap.
If the optical drive is SATA connected....
SATA data cables are supposed to latch into their sockets, but it is common for that to not work and the cable is not latched, in which case the cable can move and cause a poor connection - make sure the data cable (and power cable if it's the SATA type) doesn't move when touched or wiggled near the socket.
If in doubt, replace the data cable - a cheap thing to try.
If for whatever reason XP detects the optical drive is producing too many data errors, it will automatically set the drive to PIO mode without you knowing about it. Burner drives are often not detected as burner drives when they are in PIO mode, but may be detected as a CD-rom or a DVD-rom drive. If the drive is defective enough, XP may not see the drive at all.
After examing your data cable, with it's data cable connected, take a look at this:
If it's connection is in PIO mode, try setting it to UDMA if available, save settings, then go back in to see if it's in a UDMA mode.
If it's still in PIO mode, XP has added entries in the Registry that force the drive into PIO mode all the time. I can tell you how to remove those entries, but if the problem that caused the data errors has not been fixed, XP will set the drive to PIO mode again right away, or in a short time, and will eventually make the registry entries again.
No spin test - easy to test for.
Only the power cable needs to be connected, when the computer is powered on.
Insert a CD in the drive, note it's relative position, close the tray, let the CD try to spin, when the led goes out eject the tray - if the CD is in the same position the drive motor is not spinning at all.
If the led stays on for a long time when you insert a CD it can read, or blinks on and off for a long while, rather than lighting up briefly like it should, it's defective, for one reason or another, or it's data cable is damaged.
It may do this whether or not the data cable is connected.
If the led doesn't come on at all, the drive's logic board is fried.
The floppy drive symptoms are probably not because of the floppy drive, although you could check it's data cable too. However, floppy drives are often the first thing to fail if the computer power supply ever produces too much 5v in my experience (more than 5.5 volts) - the second most likely thing to be damaged in that situation in my experience is optical drives. E.g. Have you had a power supply die while it was connected to this computer??
The led often works, and the drive may seem fine for a short time, but eventually it can't read disks anymore, or a floppy drive may not be able to format.