|You most likely downloaded Ubuntu in ISO format, so it needs to be burned to disk using the proper software. Simply copying the ISO to a disk is useless. ImgBurn is a free burning program that will do the job.|
And if you have a SATA HDD & are trying to install XP, the drive will NOT be recognized because XP was released before SATA HDDs became mainstream devices. You will either need to change to IDE compatibility mode in the BIOS, OR press F6 at the start of the installation & load the SATA drivers from a floppy, OR create a completely new XP disk with the SATA drivers slipstreamed into it. This has been covered many, MANY times before in these forums & others. There are plenty of XP slipstream tutorials available by doing a google search. You will need a program called nLite to be able to create the new disk.