Hit with Virus that executed via PowerShell Scripting. Can I disable Powershell on my network via Group Policy and what implications does that have for me.

Question

Our network was hit recently with virus previously unknown, O97M.Crigent.  It is a nasty Macro virus that targets Microsoft Office Documents & Spreadsheets and uses a combination of Macros and Scripts via Powershell. 
How do I disable PowerShell scripting via Group Policy?
Will this raise any issues such as random application or network failures or other issues?
Can I apply it to the entire domain or should I be selective and only apply it to the workstations?
Network Summary: Windows 2008 Active Directoy Server, 75% Windows 7, 25% Windows XP workstations.
DouglasOfSanMarcos

Answer 1

Disabling Windows PowerShell can be done with GPO:
Computer Configuration | Administrative Templates | Windows Components | Windows PowerShell
From GPO Description: "This setting exists under both "Computer Configuration" and "User Configuration" in the group policy editor. The "Computer Configuration" has precedence over "User Configuration."
By default this option is restricted any way on computers.
I would be very selective when apply it at all:
Workstations - I would apply to test group of workstations first, just to see that there are no side effects before applying to all computers. 
Server - I wouldn't apply it at all. I have seen too many issues when setting this policy on Exchange and other systems.
 If you are using a Group Policy to define a PowerShell logon, logoff or computer script, that script will disregard any execution policy set locally or through a GPO.
http://4sysops.com/archives/set-powershell-execution-policy-with-group-policy/
http://technet.microsoft.com/en-us/library/hh849812.aspx
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