Tied how? Certainly not legally. When you buy the computer you buy a license... no court would uphold charging people for something and not letting them have it.
The "shrinkwrapped" license agreements are not really enforcable... at least not in a legitimate (eg: competant) court.
Actually yes legally. You never buy the software. You are always buying the right to use the software under a set of circumstances. OEM Licenses are licenses sold under the basis of being tied to a single physical piece of hardware.
Personally I don't think it is fair, but that's how licensing works under a monopoly.
Jonathan Allen