I fkd my bios settings blank screen

Hello,
Ok last night I was drunk and wanted to overclock my cpu as it is rubbish when I found that it would not let me I thought it would be an excellent idea to mess about with other settings. I changed my input/output (not sure) to not be vga anymore so it doesnt recognise my vga monitor, when i booted up screen was blank tho I cud hear the windows log on music and everything. I presume that I should reset my bios I would load optomized defaults but I cant see what I'm doing. Should I take out the mobo battery and drain the power to reset my bios. p.s. I have no manual for my tower. Much obliged to anyone that can help.