To disable Autorun system wide (for all users) on all the drives:

save the following script as .reg -file and double-click it (melt it with registry)

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Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer]
“HonorAutoRunSetting”=dword:00000001
“NoDriveTypeAutoRun”=dword:000000ff

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You may find it a bit annoying to have it disabled on the CD drives, to
disable Autorun on all but CD drives use this:

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Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer]
“HonorAutoRunSetting”=dword:00000001
“NoDriveTypeAutoRun”=dword:000000df

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be secured!