My Ubuntu's version is 12.04. Right now I'm using Windows, but as I've burned an Ubuntu image disk to a DVD, I want to know if it's possible to install programs on it, just to test them. Will it damage any part of the live DVD? I don't really want them to be there all the time. Is just for testing.
Well, you CAN in fact install programs on it. It will work just like a normal system.
But this will all be true only till you reboot. Once you reboot, everything is gone, as the programs are stored in RAM.
So, again, you CAN install programs, its just that they won't remain there across reboots, unless you have set up a persistence file. Softwares like Unetbootin have a option to quickly do that.
Not really. Your live DVD is only storing datas in your RAM.
So, if you want to store informations/programs, you'll have to build your own persistant bootdisk.
You can look at the following website : http://www.tuxgarage.com/2011/06/create-persistent-bootable-usb-drive.html