when I boot my computer from usb to install ubuntu it says install ubuntu and then I press enter and after that it says /install/vmlinuz: file not found

Please verify the md5sum of your cd
     https://help.ubuntu.com/community/HowToMD5SUM

Here some general info on howto made a bootable usb stick with Ubuntu netbook on it...

- 1) Download ubuntu-10.10-netbook-i386.iso from http://releases.ubuntu.com/10.10/

http://releases.ubuntu.com/10.10/ubuntu-10.10-netbook-i386.iso

NOTE: to get best download errors check please prefer the torrent protocol to download the iso image

http://releases.ubuntu.com/10.10/ubuntu-10.10-netbook-i386.iso.torrent

If you are using Windows, install Deluge torrent client: http://deluge-torrent.org/
if you are using Ubuntu you have already trasmission installed to manage the .torrents files (you can also install Deluge on Ubuntu).

The torrent protocol have good download errors checking, downloading using the http or ftp protocol may result with a file with errors in it.

- 2) (VERY IMPORTANT POINT) check the md5sum of downloaded iso image

https://help.ubuntu.com/community/HowToMD5SUM

if the md5 of downloaded iso image doesn't match with the md5sum on this page:

http://releases.ubuntu.com/maverick/MD5SUMS

redownload the iso image again (please use the torrent protocol) or you are going to waste your time by try to install Ubuntu from a bad iso image.

( we must ALWAYS check the md5sum of downloed iso images before to burn it to a cd or to tranfert on a usb stick ) .

- 3) install and use unetbootin http://unetbootin.sourceforge.net/ to put on the usb stick the md5 verified iso image.
     unetbootin can be installed and used on Ubuntu and on Windows...

- 4) boot your pc from the usbstick (you may need configure your bios) and install Ubuntu

New to Ubuntu: read the Ubuntu Manual, it's very informative: http://ubuntu-manual.org/
Click on the "download Button" to download the latest PDF version.
The online help https://help.ubuntu.com/10.04/index.html

Relax and fun:
http://planet.ubuntu.com/ and Full Circle Magazine http://fullcirclemagazine.org/

Boot on Ubuntu CD, "Try without install", mount partition which contains /boot.
Then check that vmlinuz file described in /boot/grub/grub.cfg exists in /boot.