I Messed up - Could not start compilationWin32Exception: on all projects o reinstalled and it happened.

I have made a huge error somewhere. I was happily building a simple game i got the template for and the demos worked fine. Then on the final build i got this compiler error - the other projects worked fine but jsut on one project. couldnt get it to work, tried the delete library etc.

then i tried to rebuild another project and it happened there as well.

I reinstalled unity, and now nothign works, it wont even play in the window never mind build to android etc.

I looked at the SDK location and fairly sure its OK, but willing to try again. I do keep my projects on a separate partition as i have a fast and slow hard disk in the PC and the operating one is faster so i keep data on the other one.

Any ideas, kinda panicing!

this is the error

Could not start compilationWin32Exception: ApplicationName='"C:\Program Files\Unity\Editor\Data\MonoBleedingEdge\bin\mono.exe"', CommandLine='"C:\Program Files\Unity\Editor\Data\MonoBleedingEdge\lib\mono\4.5\mcs.exe" @Temp/UnityTempFile-64a595c02ab18d248a60500c36956bc8', CurrentDirectory='D:/Unity information/Halloween matching2/Assets/..' System.Diagnostics.Process.Start_noshell (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process) System.Diagnostics.Process.Start_common (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process) System.Diagnostics.Process.Start () (wrapper remoting-invoke-with-check) System.Diagnostics.Process:Start () UnityEditor.Utils.Program.Start (System.EventHandler exitCallback) (at C:/buildslave/unity/build/Editor/Mono/Utils/Program.cs:44) UnityEditor.Utils.Program.Start () (at C:/buildslave/unity/build/Editor/Mono/Utils/Program.cs:28) UnityEditor.Scripting.Compilers.MonoScriptCompilerBase.StartCompiler (BuildTarget target, System.String compiler, System.Collections.Generic.List`1 arguments, Boolean setMonoEnvironmentVariables, System.String monodistro) (at C:/buildslave/unity/build/Editor/Mono/Scripting/Compilers/MonoScriptCompilerBase.cs:33) UnityEditor.Scripting.Compilers.MonoCSharpCompiler.StartCompiler () (at C:/buildslave/unity/build/Editor/Mono/Scripting/Compilers/MonoCSharpCompiler.cs:63) UnityEditor.Scripting.Compilers.ScriptCompilerBase.BeginCompiling () (at C:/buildslave/unity/build/Editor/Mono/Scripting/Compilers/ScriptCompilerBase.cs:40)

Not a coder really jsut been using the interface. Am basically at the reinstall winows stage of this but not even sure that would fix it.

All help or suggestions REALLY REALLY welcome