Partitioning hard drive please help

Hey everyone,
im using windows vista business.
I just bought a 500gb western digital external usb hard drive.
i am trying to partition this hard drive. this is how im trying to do it:
1. right click my computer go manage.
2. go disk management
3. right click the volume/hard drive and click shrink.
The problem is that when i right click the external hard drive it doesn't allow me to click shrink.(its an option but not colored in black its like clear and i cant click it.)
i want to avoid formatting it as i have about 150gb of files on it. its in fat32 format. are their any other things you could think of, and if i have to format it please tell me. also is it possible to partition that external hard drive.
(also if i use my mac and go to utilities it shows that hardrive and allows me to partition but to finish partitioning you must format, im just trying to avoid that because i don't want to wait for 150gb to copy. however if its the only way then i will.)

sorry its so long but i would appreciate any help or tips. thanks.

Hello Petamartt,

Welcome to Vista Forums.

You could give this a try. Best FREE Partition Manager Freeware for Windows 2000/XP/Vista/Windows 7. EASEUS free Partition Manager Software Home Edition. or this BEST FREE Partition Manager Software for Windows supports all 32-bit & 64 bit Windows No-server OS.

Links to these and many other useful free programs here: http://www.vistax64.com/software/115872-free-software-list-vista.html

Hope this helps.

Gary

I found that solution in an other post and it work

http://www.vistax64.com/vista-general/276426-re-partitioning-hard-drive-please-help.html

but I still like to know why it has put that drive as the second drive.... on top of that allocating 60mb to what use??