This has gone on waaay to long
1) Remove the "NvMediaCenter" reference from the startup "Run" sequence.
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
;"NvMediaCenter"="RunDLL32.exe NvMCTray.dll,NvTaskbarInit"
"NvMediaCenter"=-
As you can see from the above "example", the original reference is to initialize the tray icon automatically from the startup "Run" sequence when (re-)booting your computer (it is delineated with the semicolon). In the third line, the hyphen after the equal sign will remove that reference automatically.
2) Remove the "NvCpl.dll" reference from the nVIDIA "MediaCenterTray" registry entry.
;[HKEY_LOCAL_MACHINE\SOFTWARE\NVIDIA Corporation\Global\MediaCenterTray\NvCpl.dll]
;"FullPath"="C:\\WINDOWS\\system32\\NvCpl.dll"
[-HKEY_LOCAL_MACHINE\SOFTWARE\NVIDIA Corporation\Global\MediaCenterTray\NvCpl.dll]
And from this example, you will see the original references (first two lines delineated with semicolons). It seems if they remain there, the taskbar icon will continue to reappear until the reference is completely removed, so to do this, the hyphen (just after the left square bracket) will remove the entire key. This is the step that most people have missed in their posts.
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NOTE: It is NOT necessary to remove all 3 nvidia driver references from the startup "Run" sequence. You only need to remove the taskbar initialization reference and the NvCpl.dll registry key.
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For easy copying and pasting, here is the complete registry entry for a .reg file (it also includes the registry entry for removing that incessant SLI notification):
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\NVIDIA Corporation\Global\MediaCenterTray]
"NvCplDisableBalloonNotifications"=dword:00000001
;[HKEY_LOCAL_MACHINE\SOFTWARE\NVIDIA Corporation\Global\MediaCenterTray\NvCpl.dll]
;"FullPath"="C:\\WINDOWS\\system32\\NvCpl.dll"
[-HKEY_LOCAL_MACHINE\SOFTWARE\NVIDIA Corporation\Global\MediaCenterTray\NvCpl.dll]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
;"NvMediaCenter"="RunDLL32.exe NvMCTray.dll,NvTaskbarInit"
"NvMediaCenter"=-
"NvCplDaemon"="RUNDLL32.EXE C:\\WINDOWS\\system32\\NvCpl.dll,NvStartup"
;"NvCplDaemon"=-
"nwiz"="nwiz.exe /install"
;"nwiz"=-