Help...Startup Manager of my Macbook air can't detect any USB and External

[psycho_606]

Good day po Symbianizers,

pa Help naman...Startup Manager of my Macbook air can't detect any USB and External. Bale mag clean install po ako ng OS X mavericks or lion.
napapalabas ko naman yung ung startup manager pero ung hdisk lng ng macbook air ung nadedetect nya. wala ung USB or external disk n kinakabit ko.

Ano po kayang need ko gawin..

TIA more power po sa inyong lahat

 

[praetorius]

punta ka ng disk utility. pag makita mo dun ang usb drive, try mo i-mount