Actually, I think it might fit. The HD has a T-shaped "foam spacer" on one side of it. You could trim 3mm off the width of that spacer and it would be ok...the only problem you might have is the clearance of the connector. I remember when replacing my stock 80G HD with a 200G Hitachi you have to "lift" the connector end of the drive a little to get it to engage, so there is a little clearance...not sure if it's enough for a 3mm bigger drive....but if the connector is offset a little - and not centered on the 500G drive, it might be fine (assuming it's offset to the correct side)