Windows 7 - Problem in recognizing HDD data!

Hello, out of no where this two problems happened to me:-

1. when i connect my 1 tera HDD, it shows in my computer, but;
it's shows that its only 457 GB & it's completely empty!
also i can't access it or do anything about it.
one more thing; i remember that it had at lease 700 GB of data.

2. also when i connect my 4 tera HDD, nothing happens;
it even doesn't show up in the Disk Management.
with this one i tried USB & eSata cables, neither have worked.

* PS: both of them have electricity power supply,
& when i connect to the computer the sound coming of them changes:
it says that they know that they are connected to the computer!!!!!!!!

Hi

What make and model HDD's are you connecting?

Regards
UKMedia

1 Tera HDD: iomega, MDHD10T-UE
4 Tera HDD: Western Digital, WD40000H2Q-00
I wrote there model, if you don't mean manufacture model, tell me what you need!

Okay, lets do this one at a time. Have you downloaded the latest software from here:

https://iomega-eu-en.custhelp.com/app/subproduct/p/1031

and

WD Support / Installation / My Book / My Book Studio Edition II


Regards
UKMedia

i have already done that, but didn't work.
one more thing i have another two WD HDD
2 Tera & another 4 Tera; they work just fine.

Hi

When you connect these via SATA cables, can you see them in the BIOS?

Regards
UKMedia