MyBook 1TB freezes when administration GUI is accessed from Windows 7

I have a very strange problem. The MyBook drive worked without a problem for months when using being used with a Windows XP. Since I upgraded to Windows 7 it also works but with one exception: it seems that 1 or 2 minutes after I access the Administration Web GUI no matter what I do in the GUI it just freezes. It responds to ping but none of its other functions (even ssh) are accessible anymore until I reboot it. Just for a try I switched back to Windows XP without changing anything on the MyBook and it works again until I reinstall Windows 7 and access the GUI it from it. I can even access it from my PDA without a problem but not from Win7! What could be the reason for that?

I´ve contacted the WD support and after some mails they actually gave me the solution to that problem so if you have a similar issue be sure to try the following:

Windows 7 Control Panel > Administrative Tools > Local Security Policy > Local Policies > Security Options

Network Security : LAN Manager Authentication Level
Send LM & NTLM responses

Network Security: Minimum session security for NTLM SSP
Disable require 128-bit encryption