I'm not really sure where to post this, so I'll put it here and it can be moved if necessary. I have spent a long time recently installing and reinstalling the .NET Framework in order to play a game (Terraria), but it has never worked properly, giving me various errors. I have a log of the most recent install failure here. Can anybody help me? OS Version = 6.1.7601, Platform 2, Service Pack 1 OS Description = Windows 7 - x64 Home Premium Edition Service Pack 1 CommandLine = I:\248853e1b9917d70215c868228\\Setup.exe /x86 /x64 TimeZone = GMT Standard Time Initial LCID = 1033 Using Simultaneous Download and Install mechanism Operation: Installing Package Name = Microsoft .NET Framework 4 Setup Package Version = 4.0.30319 User Experience Data Collection Policy: Disabled Number of applicable items: 11 Exe (I:\248853e1b9917d70215c868228\SetupUtility.exe) succeeded. Exe Log File: dd_SetupUtility.txt ServiceControl operation succeeded! ServiceControl operation succeeded! Exe (I:\248853e1b9917d70215c868228\Windows6.1-KB958488-v6001-x64.msu) failed with 0x240006 - (null). Exe (I:\248853e1b9917d70215c868228\SetupUtility.exe) succeeded. Exe Log File: dd_SetupUtility.txt MSI (I:\248853e1b9917d70215c868228\netfx_Core_x64.msi) Installation failed. Msi Log: Microsoft .NET Framework 4 Setup_20111229_152948055-MSI_netfx_Core_x64.msi.txt Final Result: Installation failed with error code: (0x80070643), "Fatal error during installation. " (Elapsed time: 0 00:01:10).