Returning HD to Maxtor - How To Prepare?

I have a failing drive from Maxtor that will be returned when I
receive the warranty replacement. There is a lot of confidential data
on this drive. What is the best way to clear the data? A low-level
format? It would be just my luck for the low-level format to fix
whatever the problem is so Maxtor would tell me there was no failure
found, and charge me for the replacement drive. Would they do that?

As far as wiping confidential data goes, I'd say using a low-level
formatting tool is a good idea. I have them for Seagate and Fujitsu
drives, so I presume Maxtor will have one for download on their
website somewhere, probably in their downloads or support section.

Be aware it can take a while to complete a low level format depending
on your PC - took me nearly 24hours to wipe a 160GB drive on a 1.1GHz
PC.
I think it writes data to the entire drive, rendering it 'as new' as
it were.

If you don't use an LLF tool, at least use something like BCWipe to
destroy all your data - you can do it several times, depending on your
paranoia level
I'm sure you know that a plain old 'format C:/' doesn't actually
destroy data, merely flagging it 'deleted'.