Internal backup drives not being detected in 8.1

Hi i have just installed windows 8.1 64Bit on my pc which was originally running windows 7 64Bit I have 2 internal backup drives in addition to my normal boot drive Both these drives have data and worked perfect in Windows 7 but in Windows 8.1 only one shows up When i try to access the one I can see it says drive not accessible Access denied It also shows used space and free space as zero bytes When i know it is at least half full.

Its a 2 terabyte drive same as i the one i cannot see at all I have uninstalled both drives reinstalled them updated every driver possible I have windows 8.1 on a slide in drive as windows 7 When i slide Windows 7 back into the same machine both drives show up no problem.

Its an ASUS M4A785TD-V EVO Motherboard I am begining to wonder would a Bios update help if there still is one available

As this motherboard is getting on a bit now.

Anybody else have same problem.

Thanks Ronnie

Do you know what hard drive setting you had in Win 7, ACHI or SATA? Your new system may be set for one and it's giving you problems accessing the drives if they previous were operating on the other. Also, check your BIOS setting to see what your mobo is set to.

Check your settings in Windows 8, but be careful switching from one to the other. Then search for how to switch. Depending on your exact circumstances, you should be able to find a procedure that matches your situation.

Did you try connecting it to another SATA port on MB ?