External Harddrive Problem?

[Teny]

so i bought an WD Passport Essential external hard drive.
its a small hard drive that only connects to a usb, and does not require a power cord.
its a 160gb external. and i have about 100 gb of free space.
but whenever i try to put a file, i think its about 4 gb and over, it says that the disk is full and ask me if i want to do a disk cleanup, which there is nothing to clean up.
heres a link from newegg.
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136246
thanks in advance

EDIT
Nevermind, i figured it out, i had to reformat it to NTFS

 

[IAntDemo]

yer i was going to say that, i have the same hdd and plugged it in ps3 and it fucked up my hdd so i plugged it in and nothing showed up in mycomputer, but i checked disk management and it was their unallocated space so i had to do a NTFS format.

good harddrives them with the blue light and a slick feel and size.