I can successfully boot from USB, the ubuntu purple screen comes. 2 options pop up: Try ubuntu & Install Ubuntu. After Clicking install ubuntu, in the next step memory space allocation is made, admin password is given. then "continue" is clicked. Ubuntu purple screen comes up, pc shuts down and reboots from USB again. Then the process repeats.. Pls help to resolve this issue.
Your install media is probably corrupt. When booting the install media there is an option to "Check CD for defects" this is somewhat misnamed. It really is a file-integrity checker, but the other way sounds better. Do that "Check CD for defects". Your files are probably @#$!. Also give us more info: How much Memory do you have? Which version of Ubuntu are you using? et. al.