What kind of executables are you wanting to run?
How do you want to connecto to the internet? Is it through a LAN or dialup?
It would all depend on if your modem is supported or not! Which distro are you using? It might already be supported! If you have a winmodem though, there is a fat chance you won't get it working.
And to create accounts in Linux just type adduser at the bash prompt.
# adduser thenusernamehere
# passwd thenusername < to set the password for user.