did you try to remove the program from add/remove or start all programs and uninstall. is the program still in all program listed.
when your pc is starting up keep pressing f8 then choose safemode
login as normal not admin unless you don't have admin rights
go to control panel, add or remove if you still get the same error
click on start, my computer, program files, find the file nero delete it and delete it from recycle bin.
then click on start, run, type regedit, expand HKEY_local_machine by clicking the plus sign
then expand software and find nero and delete.
please don't delete anything else us you will have corrupt registry or unusable pc if you are not sure or need more advice then just delte the program files.