Try this :
Press crtl+alt+delete
now delete the explorer process from the process tab.
the desktop and taskbar will vanish
now, go to the applications tab and click on new task and type "explorer.exe" in it.
Cllick on ok.
Now taskbar and desktop should reappear.
Now see if the explorer.exe still eats cpu...
But a downside is that the winmx icon in the tray will not appear.
although winmx will be still there if you click on the x at the topright of the screen
To reopen winmx, click on the winmx shortcut
To close winmx, end the winmx.exe process in the task manager
Cheers