NEED HELP!!!! External HDD problem

Just recently bought a WD Elements 1tb external HDD

I put all of my videos, music and apps on it and now it won't show up in mac os x.
2 partitions, formatted to MS-DOS FAT and Mac Os Journaled.

I plugged it into my laptop this morning and the Mac os journaled didnt show up. I then copied some files over the the MS-Dos partition and then all of a sudden all folders were empty (i checked before and they were all there).

I unplugged everything and kept it off for a while then plugged it back in and tried to repair the HDD. I dont know how but the Mac Os journaled repaired and is now working but the MS-Dos is not showing up and has this message when i try to verify/repair he disk:

Invalid BS_jmpBoot in boot block: 6bf3d4

It said this for the mac os partition before but then i tried again and it fixed itself. I basically have everything on the MS-Dos partition and now it doesnt work.

Running on a white macbook 2008 2.4ghz model, Mac os x 10.5.6

Can anyone help me???

 

If you have a windows computer available try running a check disk on it. Type CHKDSK volume in the command prompt.
If you do that, be careful not to erase you OSX partition when you plug it in. It sounds like you know how to use the disk utility, may try checking the permissions as well.
Also consider that if you added files that where over 4GB to the drive, that may be the problem. It should not have let you add them because the FAT partition does not support files over 4GB but if it did then that may be your problem.