i have vista on my dell latitude D260. i wanted to 'upgrade' to ubuntu , so i downloaded and burnt the image onto a cd . when i try to boot via the cd nothing ever happens. in this lappie , when i go to bios tit asks me to give preferences to the booting order so i gave 1 to the CD and unchecked the others but when it statrs again the it doesnt recognise the cd and refuses to boot from it . what can i do?

Test the CD in another system to make sure the CD burn and the image are good.

If it tests well, then look for a startup boot menu. Many systems let you hit F12 or something to manually select the boot device.

agree with CimmerianX, make sure that the disc is bootable. :)

For full compatibility, when burning a disc, you should burn the disc on ISO level 1 using ISO 9660 character set and no relaxed restrictions. If after following the recommendations of the previous two respondents, you still can't boot, I would recommend burning a new ISO disc following the above recommendations.