Can't access BIOS (No OS)!

[UnknownOBEY]

I have just built a pc and turned it on. I had my keyboard plugged in and pressed del to get into the BIOS. Nothing happened. Then there was 3 short beeps that happened and it asks to "reboot and select proper boot device or insert boot media in selected boot device and press a key" I have windows 8 on a usb. So i put it in and press a key. Nothing works. Then it just sits there. I Have removed the CMOS and did a reset. That also doesn't work. My specs are:
Motherboard: Biostar TA870u3+
Processor: AMD Phenom II
Power Supply: CX600 ATX
Graphics Card: GeForce GT 650
Hard Drive: 1 TB WB Sata

 

[lukapavlinovi]

Try some other key. There should be a screen with keys listed on startup. If it is Del key then try tapping it multiple times or hold it for a bit.

 

[Lumber-jack]

or you could check what 3 beeps is for the bios that is on the MB