RNUPGAGENT.EXE is Real Networks Update process.
I had my own experience with Real Player some years ago and I got rid of it. Real player is part of the RealNetworks at http://www.realnetworks.com/
At that time, (and I will try to restrict my comments to what happened all those years ago), I downloaded the RealPlayer media player. But as soon as I installed it, it started to take over my computer, with RealPlayer and all sorts of other RealNetworks components. Things like its own control panel and constant information received from the web site.
Trying to shut it down took a lot of work as it has options all over the place. For example, preventing it from "loading at startup" took a number of attempts because that option is duplicated or triplicated around and about in options. Every time I killed a process, another one would pop up.
After a while I uninstalled anything I could find to uninstall, then I got the hatchet and began deleting all files and folders to do with RealNetworks and RealPlayer, then started on the registry.
Eventually I got control back, but it was messy.
They may be different nowadays.
Mark
I shut down realplayerupdate and suddenly this show up as running. When I went and searched online for what this file was/did...I ended up here. I also found these sites saying that it can be bad or good, but not much clarification other than to download their "free" file checkers.
Does anyone know anything about this file exe definitively?
These are the sites:
http://www.file.net/process/rnupgagent.exe.html and
http://systemexplorer.net/db/rnupgagent.exe.html
Anyone is probably more adapt at understanding this stuff than I am. So I am looking for someone to explain it in very basic, easy layman's terms.
Thank you,
Kinga

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic