cursor flashes cd symbol

[fanob5]

I am running XP Pro with sp2. My main cursor keeps flashing a cd symbol every second. This does not happen with any of the other cursors (eg working, waiting, text select, etc.), only the main select cursor. It doesn't matter if there is a disk in any of the optical drives. I changed the cursor, but this did not help either.
Any ideas on how to get rid of this annoyance?

Thanks in advance!