My files disappeared on my hard drive!

[computer1000]

I have a Maxtor OneTouch III Turbo Edition 1TB Hard Drive Array 7200RPM, External, USB 2.0 / FireWire 400 / FireWire 800

Now I just connected it by USB cable to my computer and I found out all my video files and digital media I saved there before disappeared!  I know they are still there because when I check the drive in the My Computer screen they found 300gb used but when I click on the drive and highlight all the folders and files theres 50gb less!  What kind of data recovery software do i need to find my invisible files??

[GX1_Man]

What happened from when it worked to when it didn't?

When you right click on the drive and choose properties, what does it show?

What CAN you access on the drive? Was it encrypted in any way? Does this help?

http://support.microsoft.com/kb/308421