i have  the ubuntu disk and i have a usb cd rom drive how do u make the laptop boot from there.

Disk drive

I have no idea whether this is possible or not but I would think it's your best bet. Enter the bios by following the instructions for your motherboard giving in the text on startup. From there you should be able to change the drive priorities of where the computer boots from. If it has recognised your USB drive by this stage then you should be able to set it as the first device you want it to boot from and then ubuntu will load when you restart.