That's non-informative. Please write down the error text (crashing address) otherwise it's no use. 1. Windows Me 2. KernelEx 4.0 Final Problem: 1-Installing KernelEx 4.0 Final with the Recommended setting of enabling all applications. Upon reboot, error message : "Runonce has caused an error in KERNELEX.DLL". The system is blocked and I have to restart in Safe Mode to uninstall KernelEx 4.0 Final 2-Installing KernelEx 4.0 Final with Disable KernelEx extensions. Upon reboot, several error messages : "Verify has caused an error in KERNELEX.DLL" "Explorer has caused an error in KERNELEX.DLL" not start PDFXChangeViewer, error message : "PDFXCVIEW.EXE file is linked to missing export KERNEL32.DLL: SetFilePointerEx" not start Adobe Reader 7.0.9, error message : "Acrord32 has caused an error in KERNELEX.DLL" No problem with running KernelEx 4.0 RC2 which works very well