I have a late 2009 21.5" iMac. It has a mini display port. Its hard drive has been formatted, and I haven't re-installed OSX yet (and don't want to if I don't have to).

I'd like to use the iMac as an external display for a windows PC that has a display port.

Before I buy a mini-display port to display port adapter. How can I tell the requirements for this iMac to support target display mode?