I have a 50Gb Maxtor hard drive.
I have set up 3 partitions.
Upon formatting the 1st partition a message appeared:
Trying to recover an allocation unit...
Does this mean the hard drive is damaged?
If not what course of action is recommended?

PowerMax v4.21 (01.25.2005)
The PowerMax utility is designed to perform diagnostic read/write verifications on Maxtor and Quantum hard drives. These tests will determine hard drive integrity. The PowerMax utility is effective on all ATA (IDE) hard drives with a capacity greater than or equal to 500 MB. Maxtor recommends the use of this utility for troubleshooting potential hard drive problems.

- Download PowerMax (English | Direct Link | 0.94 MB)

If FORMAT stutters during its progress and says it is trying to "recover an allocation unit", chances are that the drive has sustained some physical damage and has bad sectors. If you were out of the room and missed this, a summary of the drive, including of any bad sectors, will be displayed at the end of the format process.

To look further at any bad sectors, use the SCANDISK utility, and run a surface scan. If there are only one or two bad sectors, and their location is apparently random, it's likely the drive has been damaged. However if you find large numbers of bad sectors, either in some sort of a pattern, or all starting at one point, it is possible that the drive has not been properly set up in CMOS.

Normally the presence of bad sectors is an indication that a drive is 'on it's way out'. However if the bad area is not too big, and is located toward the end, you might consider repartitioning the drive to use just that part of the drive that is unaffected. This practice is not recommended for a system where data integrity is important.

Thank you, I have downloaded & will give it a run.
Another question if I may.
Figuring I may need to get a new hard drive,
What is the difference between a 2.5 & 3.5 hard drive other than the obvious size.

Cancel the question about the 3.5 and 2.5 hard drives.
Duuuu!
2.5 for laptops
3.5 for desktops

Got it sorted.