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explorer.exe

What is it?
Windows Explorer - explorer.exe

What does it do?
explorer.exe - Below is a direct quote from Microsoft found on THIS page:

This is the user shell, which we see as the familiar taskbar, desktop, and so on. This process isn't as vital to the running of Windows as you might expect, and can be stopped (and restarted) from Task Manager, usually with no negative side effects on the system.

I have found that stopping this process is needed sometimes to stop some other processes.

More Info
More Info

Virus Precaution:
The original file from Microsoft gets placed at C:WINDOWSSystem32explorer.exe . if you find it anywhere else then you should be suspicious for sure.

You'll want to keep an eye on this google search for any known viruses. There's only one unique virus found through this search. All of the results are the various names of this single virus.

Deloder-A @ Sophos
MyDoom.B @ Symantec