As far as I know, the Windows shell (explorer.exe) doesn't load kernel level related components. If you believe a component loaded during starting explorer.exe that kills explorer.exe, you can try to find it out yourself by running Autorun
Run it and go to Everything tab, if you spot the DLL you write or any suspicious ones (e.g. from Cypress DDK), disable them.
Unable to restore to a previous checkpoint is a bit weird though.
Are you sure that your PC has not been infected by virus or spyware/malware?