Don't you have to activate it within 30 days for it to work at all, or is there a way around that? I never found out since I activated it with 2 days left.
I don't know how it works where you live, but here in the UK you can only install a piece of software onto one computer. If you want to install the same thing on another computer, you have to go and buy another one. As far as I know that's how it works anywhere in the world. So using your brother's XP CD on your computer is illegal.
If it's just a regular XP CD, than it should work. But i hope that you're not talking about some Dell System Restore CD, Cuz then there would be a problem.(It just wouldn't work )
Most of the newer dells come with a complete Win XP operating system on 1 disk and the software on another disk, thus it is not the same as a restore disk.