Adding this to your registry will give you the ability to build/clean/rebuild projects using the right click in windows explorer.  It uses .net 4.0 version of msbuild.  Just paste this into a .reg file and run it.

Windows Registry Editor Version 5.00 

[HKEY_CLASSES_ROOTSystemFileAssociations.sln] 

[HKEY_CLASSES_ROOTSystemFileAssociations.slnshell] 

[HKEY_CLASSES_ROOTSystemFileAssociations.slnshellBuild] 

[HKEY_CLASSES_ROOTSystemFileAssociations.slnshellBuildcommand] 
@="cmd.exe /K ""%%windir%%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe" "%1" /t:build"" 

[HKEY_CLASSES_ROOTSystemFileAssociations.slnshellClean] 

[HKEY_CLASSES_ROOTSystemFileAssociations.slnshellCleancommand] 
@="cmd.exe /K ""%%windir%%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe" "%1" /t:clean""

[HKEY_CLASSES_ROOTSystemFileAssociations.slnshellRebuild] 

[HKEY_CLASSES_ROOTSystemFileAssociations.slnshellRebuildcommand] 
@="cmd.exe /K ""%%windir%%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe" "%1" /t:rebuild""

[HKEY_CLASSES_ROOTSystemFileAssociations.csproj] 

[HKEY_CLASSES_ROOTSystemFileAssociations.csprojshell] 

[HKEY_CLASSES_ROOTSystemFileAssociations.csprojshellBuild] 

[HKEY_CLASSES_ROOTSystemFileAssociations.csprojshellBuildcommand] 
@="cmd.exe /K ""%%windir%%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe" "%1" /t:build""

[HKEY_CLASSES_ROOTSystemFileAssociations.csprojshellClean] 

[HKEY_CLASSES_ROOTSystemFileAssociations.csprojshellCleancommand] 
@="cmd.exe /K ""%%windir%%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe" "%1" /t:clean""

[HKEY_CLASSES_ROOTSystemFileAssociations.csprojshellRebuild] 

[HKEY_CLASSES_ROOTSystemFileAssociations.csprojshellRebuildcommand] 
@="cmd.exe /K ""%%windir%%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe" "%1" /t:rebuild""

[HKEY_CLASSES_ROOTSystemFileAssociations.vbproj] 

[HKEY_CLASSES_ROOTSystemFileAssociations.vbprojshell] 

[HKEY_CLASSES_ROOTSystemFileAssociations.vbprojshellBuild] 

[HKEY_CLASSES_ROOTSystemFileAssociations.vbprojshellBuildcommand] 
@="cmd.exe /K ""%%windir%%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe" "%1" /t:build""

[HKEY_CLASSES_ROOTSystemFileAssociations.vbprojshellClean] 

[HKEY_CLASSES_ROOTSystemFileAssociations.vbprojshellCleancommand] 
@="cmd.exe /K ""%%windir%%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe" "%1" /t:clean""
[HKEY_CLASSES_ROOTSystemFileAssociations.vbprojshellRebuild] 

[HKEY_CLASSES_ROOTSystemFileAssociations.vbprojshellRebuildcommand] 
@="cmd.exe /K ""%%windir%%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe" "%1" /t:rebuild""