Start the PC in safe mode pressing F8. When it starts up, press the windows key and the R button - should bring up the run box. Type in regedit. Browse to HKLM/Software/Microsoft/windows nt/current version/profile list.
Delete all the profiles with the long numbers. There should be three with shorter numbers - do not delete those.
Restart your PC.
We've recently had this issue and can solve it with my eyes closed
Thanks for the help - did not go totally to plan as AVG decided to play silly buggers and would not update or uninstall. Eventually decided to restore - which AVG did not like at all
Have this morning ordered an iMac - might as well have fun in my dotage
Thanks again for your help