I have some limited knowledge for Adobe reader 9 registry entry. You can inspect the registry location in the following inf first. The inf is to restore Adobe reader 8,9,10,11 to a uninstallable state if some pdf program breaks Adobe reader install/uninstall routine. I strongly suggest before you 'right-click' the inf, and select 'Install', do a manual backup of these registry location in case you wish to restore back to where you are before you run this inf. (Your milegae may varies) The registry location I said to make a backup are in the INF. After run the inf, use Add/remove panel to remove Adobe reader 9. (I assume you can still launch the Adobe Reader 9 uninstaller) Hopefully it will works. RestoreAdobeRdr9.txt Rename RestoreAdobeRdr9.txt to RestoreAdobeRdr9.inf ;Restore Adobe Reader 9 [Version] Signature=$Windows NT$ [DefaultInstall] AddReg =REGEntries.AddReg [REGEntries.AddReg] HKLM,SOFTWARE\Classes\.pdf,Content Type,0x0,application/pdf HKLM,SOFTWARE\Classes\.pdf,,0x0,AcroExch.Document HKLM,SOFTWARE\Classes\.pdf\OpenWithList\AcroRd32.exe,,0x10 HKLM,SOFTWARE\Classes\.pdf\OpenWithList\AcroRd32.exe,,0x0 HKLM,SOFTWARE\Classes\MIME\Database\Content Type\application/pdf,Extension,0x0,.pdf HKLM,SOFTWARE\Classes\MIME\Database\Content Type\application/pdf,CLSID,0x0,{CA8A9780-280D-11CF-A24D-444553540000} HKLM,SOFTWARE\Classes\MIME\Database\Content Type\application/vnd.fdf,Extension,0x0,.fdf HKLM,SOFTWARE\Classes\MIME\Database\Content Type\application/vnd.fdf,CLSID,0x0,{CA8A9780-280D-11CF-A24D-444553540000} HKLM,SOFTWARE\Microsoft\Windows\CurrentVersion\PreviewHandlers,{49400A7C-81A8-4F52-8CCE-D54739EE87EC},0x0,Adobe PDF Preview Handler HKLM,SOFTWARE\Microsoft\Windows\CurrentVersion\PreviewHandlers,{DC6EFB56-9CFA-464D-8880-44885D7DC193},0x0,Adobe PDF Preview Handler for Vista