Need to Reformat My External Mac HDD ->Windows..

hi all. Im a dedicated mac user now but i have friends who arent and one guy was having trouble with an external harddrive. Its a brand new 300gb drive and we initially put it in a case from maplins,which didnt support large drives. So it got stuck at 127gb even in a better caddy, then the only machine i had spare to format it in was an xbox. This got the capacity back to 300gb and i then took it to my iMac to format it in the new caddy.
I selected Mac Os extended and it works fine on my computers, but not on a windows machine.I also tried to format it using the unix file system in disk utility and it still wont work. The windows device manager profile allows me to 'populate' the drive and it recognises the 300gb, but says its not initialised and windows wont mount the disk.
I am a bit stuck now! I want it to be a windows drive instead

you might need to partition it. it has been a long time but i think i remember that windows drives can only be about 130 gigs?? i may be very wrong, but good luck!

edit: check this: http://techpatterns.com/forums/about260.html

Windows will not read Mac Os Extended nor Unix format. There should be an DOS option in the formatter. That is FAT32 which both Windows and OSX will read.

I just checked to be sure of the name, MS-DOS File System

thanks once again to this forum and its users my problem is solved. Woohoo
I dont know how i didnt spot the ms-dos format option.
Thanks for the help