'However the CD which came with it only has drivers for Windows.', such is not required for use on a Macintosh.
'When I plug the drive into the computer's USB port it shows up in the Apple System Profiler, but I don't know how to access it, or even check to see if it's compatible with a Mac.' - the Mac has recognized the MHT2040AT; else, it would not be listed in 'Apple System Profiler'.
You will want to erase and format the MHT2040AT. To do so (assuming you do not care the data currently on the hard disk drive) ...
01. Locate and double click on 'Disk Utility', in the '/Applications/Utilities/' folder.
02. Locate and click once on your hard disk drive, listed in the left hand side column.
03. Select the 'Erase' tab, 'Mac OS Extended' in the 'Volume Format:' popup menu, enter a name in the 'Name:' text edit field, and then click on the 'Erase' button.
04. Quit 'Disk Utility'.
The external drive should now be displayed on the 'Desktop'.