Why won't my ubuntu live Cd work?

either its a bad burn or it won't work with your hardware,

ubuntu will not run on my machine without a lot of tweaking and messing, contrary to popular belief ubuntu does not work on every computer,

linux will, but ubuntu will not,

if you try a new cd and it still won't work then i suggest pclinuxos

http://www.pclinuxos.com/?page_id=180

or if you have already used a version of linux, then mandriva is the optimum choice

http://www.mandriva.com/en/downloads/one/

I can only guess,

You have probably burnt the ubuntu iso incorrectly.

an iso is a disc image

you need to burn it to a DVD or CD,

using iso burning software.

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In XP/Vista

1. Download and install Infra Recorder, a free and open-source image-burning program.

Infra Recorder : http://infrarecorder.org/?page_id=5

2. Insert a blank DVD in the drive and select Do nothing or Cancel if an autorun dialog box pops up.

3. Open Infra Recorder and click the 'Write Image' button in the main screen.

* Alternatively you can select the 'Actions' menu, then 'Burn image'.

4. Select the ISO/image file you want to use, then click 'Open'.

5. In the dialog box, click 'OK'.

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In Windows 7

1. Right-click on an ISO image and choose 'Burn disc image

.