Question : fldrclnr.dll

When I start Windows XP Pro, a window pops-up stating: RUNDLL: An exception occurred while trying to run "fldrclnr.dll, Wizard_RunDLL". I downloaded a new fldrclnr.dll ans installed it at Win32 - the problem remains. Besides, the system sometimes reboots suddenly.

Answer : fldrclnr.dll

Fldrclnr.dll is part of Microsoft's Desktop Cleanup Wizard.

Try runing System File Checker
Start > Run > sfc /scannow - note the space and have your XP CD. SFC will run and exit without any closing dialogue. To see which files, if any, have been replaced look in Event Viewer.

You could also disable via Display Properties > Desktop > Customise Desktop > General Tab > uncheck 'Run Desktop Cleanup Wizard every 60 days'