To clear CMOS, Remove Power plug from WAll, some mobos still have power. All new ones does. Next remove MOBO battery, next just CMOS clear jumper to reset defaults. Then put it all bacl and try Del as it starts
I removed the mains power from the wall, and the battery and the jumper overnight, and tried again in the morning but had no luck. It still stuck on the Gateway logo at startup no matter whether I pressed F1, F2, F10, F12, Tab, Esc, Del, etc. it wouldn't go to the BIOS.
I also tried to update the BIOS via Gongoozler's suggestion and even that didn't work, though it beeps correctly, i.e. to expect a floppy containing the new BIOS.
Unless it's the wrong BIOS, something on the m/b isn't working.