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#11
Auslogics BoostSpeed is not for Win7 and may have ruined your install.
The System flag on C means it is booting the OS and any other you have on there.
If there is no OS on D any longer then mark System REserved Inactive and delete it as it could interfere. If there is an OS still on D which you want then post back a screenshot from it so we can confirm what's boot it.
Partition - Mark as Inactive - Windows 7 Forums