Windows 8: external hardrive appears on hardware and devices

Hello,

I've recently bought a labtop with windows 8.
And i have a backup of my previous computer (a mac Pro) to which i would like to have access.
Lots of files (music and work).
But once i plug the Iomega HDD external hard drive to a USB port i don't see the storage unit as it usually appears in the 'computer/hard disk drives'.
But if i go to 'control panel/hardware and sound/devices and printers' i see 2 devices: my labtop and the Iomega external hard drive.
I can't access it.

What can i do?
I've read your thread
http://www.tomshardware.co.uk/forum/289920-14-external-...
and in the disk management i see the external drive with 3 "partitions": one is marked with "unllocated" space, another as "healthy (EFI system partition)" and the thrid one as "healthy(primary partition)"

please, all suggestions and help are welcome