This is my understanding and maybe wrong and if so, I am sure I will be corrected.

• UD.exe
  
  This is the overall program in charge. It connects to the servers and downloads the wrapper task application as shown by
  
  
• ud_1582756.exe (perhaps this number changes?)
  
  This is the wrapper task application which does things such as the graphics rendering etc. The numbers will change and are really irrelevant. One of the things it does is allow different clients to be started. One of the clients is
  
  
• WCGrid_Rosetta.exe
  
  This is program which is doing all the work. It simulates the ineratctions of the proteins to simulate things and therefore get some results.
  

There are various other files which you can find in the WCG install directory but you should just leave them alone as they will come and go depending on what the client is doing.

... yes, and make sure you are properly logged in if you can't see this icon..

UD.exe is the main agent program you run. It's the program that talks to the server and uploads/downloads data.

ud_#######.exe is what we call the wrapper task. It's purpose it to decompress the workunit files and start the real task. When the task ends, it compresses the results for upload by ud.exe. The ####### will be the same for everyone. It's updated when we release a new version of the application.

WCGrid_Rosetta.exe is the program that does all the work for the Human Proteome Folding project. It's a modified version of the Rosetta program developed by the University of Washington.

UD.exe runs at normal priority. This is so you can interact with it. The only CPU it uses is when you are viewing the graphics.

The other two processes run at the lowest priority (1), so the computation and compressing won't interfere with your normal day to day tasks.

No, there are no other processes the World Community Grid launches. Just those 3.