Hi there,
I had SQL Server 2008 R2 installed, but needed to upgrade to 2012 (x64) Developer edition, in Win7 Pro x64. I uninstalled 2008 R2 rather than upgrade, more out of ignorance than intent. When I try to install SQL Server 2012, I get a dialog with 'Could not find Database Engine startup handle' and the SQL Server and Agent services won't start.
Other errors in the event viewer relate to being unable to initialize the fallback certificate (code 1, status 20), starting the FRunCommunicationsManager thread and some 'access denied' errors copying a file to a temp user folder.
I suspect that the uninstall of 2008 has left the MSSQLSERVER user in an invalid state, but I can't see any permissions missing in secpol.msc as referenced here: http://msdn.microsoft.com/en-us/library/ms143504.aspx
Anyone have any ideas, before I re-install OS etc., from scratch.
Séamus