“Restart” problem !

I have a Gigabyte M.B. and an AMD 500 mhz
processor w/128M ram.Just put together !
When I use “restart either after downloading or from the start menu, I have no video upon reboot.The rest of the system sounds like it is reloading.Checked for bios settings and tried different video card. Nothing is working. Please help, I would appreciate it. Thank you !