Covert Monitoring - Locally Installed - Detection Methods?

Hi

How can I determine if my computer has covert monitoring software on it:

My computer is part of a larger network of computers and I'm concerned one of the others might have the ability to covertly monitor mine via installed software. I'm not talking about packet sniffers on the server or logging or anything like that, but rather something which might take screenshots, or locally log data, or transmit a feed over the LAN or something like that.

If it's of the type which can be bought commercially, or a free alternative to those which can be bought commercially, what is the best way to go about detecting it? I have full admin rights to my computer and all the other network resources.

Thanks for your help - Apologies if this is in the wrong place.