I have already burned Ubuntu to the disk. But after restarting I am not getting the language selection screen or any other option to install or try Ubuntu.
You have an UEFI or EFI computer UEFI is going to replace bios in a while. When you just boot the live cd or flash drive without entering the boot menu its going to load ubuntu like an app. When your computer starts up you will see your manufacturer logo and it will show boot options on the buttom like f* to boot etc. Choose your flashdrive or cd drive from the boot menu and it should load a purple screen.