Hey
The install code is relative to the CD and not the machine. If you have lost the install key, you can search the web and get a master key that was released some years back.
You'll never get a lost key for W98 now from MS as i am sure they are only supporting XP and Win2K, soon it will just be XP and Vista i have read.
As far as i am aware you can install any version of Windows on any system as long as you have the code that is unique to the cd. I wonder how long it will be unstill the code will be relative to the hardware (system) and the cd... Dont think this is emplyed in vista