shuuhen

Since Windows was removed, you should have a laptop without an operating system. Windows isn't tied to DOS anymore, so you don't have it as a remaining shell.

You will need to load an operating system. Like wmorri, I recommend Linux or one of the *BSDs. I find DOS to be fairly limited in comparison. With Linux or another Unix-like OS, you can have a graphical environment, but will always have full access to the command line environment. Tab-completion, command history and many other features are available and work great with your choice of terminal and shell.

On Unix-likes, you can have nasm, gas and/or yasm assemblers (possibly other options too - but these are in Gentoo's Portage system). gas is the GNU assembler and is sometimes not a command called gas (On Linux and quite possibly other Unix-likes, it could be as which would be a link to something with a longer name). Between all those assemblers, you should be able to use either Intel or AT&T syntax.

For a distribution, you might look at either Arch Linux or Puppy Linux. There are plenty of other distributions, but Arch or Puppy should allow you to have a lighter setup easier than some other distributions would.