Thanks for the reply.
The hard drive light just shows when there's activity on the IDE/SATA bus(es), so using the CD drive will cause it to light up.
I'm more surprised that it didn't do this before.
That would make sense,just seems strange that the old unit did not cause this behavior.
I also have a second machine running an old Sony dvd-rw which also does not light up the hard drive light when in use.
Can i ask,what does your machine do when using an optical drive?
Anybody else had similar experiences?