If Error 1-80004005 is encountered during FSX Acceleration activation, follow the steps below to remove it:
1) Locate the entry below by regedit.exe
2) Look at UpperFilters key. It should contain “PartMgr” only.
3) If the key shows something more, mark down what they are
before editing the key to read “PartMgr” only.
4) Start FSX, the activation dialog should be prompted.
5) Proceed and let FSX start, then exit FSX.
6) Edit back the registry key with the previous content. (This step may not be required.)