logon deny domain name is not available

My home Pc is Windows XP Pro with home networking -after windows update completed I restarted the pc but cannot login with message “The system cannot log you on now because the domain ‘abc’ is not available” The name ABC is not my workgroup name – it was my computer name. i try to use F8-safe mode -went into CMOS setup-can’t do anything- I don’t have any boot cd or diskette either-can anyone tell me how to bypass the normal user logon and get to desktop window so I can fix the doamin issue. I really need help- i try to use my laptop-Windows Vista to connect to the desktop but the network won’t display all the computers in the network…Please help
Kind Regards,
AmyE