改成這樣應該可以了
不管有沒有灌過WMP7都強制把版本號碼改成10.X


Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{6BF52A52-394A-11d3-B153-00C04F79FAA6}]
@="Microsoft Windows Media Player 8"
"IsInstalled"=dword:00000001
"Version"="10,0,0,4490"