How do I check if Adobe Acrobat XI Pro is already installed?

[SuperStave]

I have created a silent install for Adobe Acrobat XI Pro. I need to add a condition that checks if its already installed. I think its a regkey, but i am not sure which one.

Also is there a way to automatically activate the software after install?

[SuperStave]

I figured this out on my own.

ConditionType: Registry
Key Name: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Adobe\Adobe Acrobat\11.0\Installer\
Value Name: ENU_GUID
Condition: Has Value
Value: {AC76BA86-1033-FFFF-7760-000000000006}