The KVR1333D3N9/8G module you ask about is produced by Kingston memory. It is not guaranteed to be compatible.
The Kingston Part Number: KTH9600B/4G is known to work with your PC. Purchase two of them in order to have 8GB.
Reference the following thread.
Crucial Memory also does have compatible memory modules. see the following link
http://www.crucial.com/usa/en/compatible-upgrade-for/HP---Compaq/8100-elite-business-pc-(sff)