Usually when you first power on you get a message saying something like "Press F__ for boot menu". This is most often the F12 key although YMMV. Try that. If nothing works still, get your friend to buy an external DVD/CD drive.
My friend gave me his Asus X5DC to do a complete re install of the OS. There are two problems why I can't do this. First, his laptops DVD/CD player isn't working. Second, when I'm trying to boot Windows files from USB, it doesn't recognize it. It simply loads files not from the USB but from HDD. In the BIOS there are 4 options for booting - HDD, CD/DVD, Removable device and network. Now, I would guess, that USB falls into category "removable device", but, as it seems, it doesn't. Maybe there are motherboard/usb compatibility issues, that I don't know. So, I hope you understand what the problem is and are capable of helping me.
Sorry if this is in the wrong forum section, I'm a complete newbie here. Waiting for your suggestions.