Dear All,
I will soon be changing the use of my computers when my wife gets a new laptop.
My 4th computer running Win98 and Peppermint3 dule boot will be going for recycling. I need to move all the present contents of this computer to another presently running mint 13.
The mint system will be cleaned so as to receive the contents of the W98/Peppermint system.
Q. is it possible to move the contents to the other computer…
Depends what you mean by “contents” ?
If you mean, can you move the WHOLE OS to a new machine … whilst this may be possible with Peppermint, it certainly won’t work with Win98 (unless the hardware is EXACTLY the same)
If you mean, can you move the user files/docs/pics/etc. … sure.
If you mean, can you copy the ENTIRE contents of your Peppermint home folder to Mint … yes, but there may be unforeseen consequences as there are a lot of hidden config files in your home folder and these may or may not play nicely with Mint.
The mint system will be cleaned so as to receive the contents of the W98/Peppermint system.
If I understand you right then you want to replace Mint on the existing HDD (keeping disk but changing contents)
with the dualboot W98/Peppermint system from the HDD in your 4th PC.
Your options would be:
Transfer partitions (disk to disk)
You would need to clone the W98/Peppermint disk onto the Mint HDD. Making sure the Mint disk is equal or bigger
than the W98/Peppermint disk.
Once cloned then run GParted on the (exMint) disk and expand partitions to fill the disk.
The win 98 install (as Mark pointed out) will complain like mad that the hardware changed and will most likely refuse to run.
Peppermint will most likely run OK but you might run into problems if your existing setup did use the UUID insted
of /dev/sda1 type.
If that is the case then (from a LiveCD) change the disk designations in fstab.
Swap Mint disk W98/Peppermint disk.
This would be the easiest option but you could loose out on (possible) benefit of transferring to newer/faster HDD.
The Win98 caveat still applies.
Thank you for the answers. This will not happen for a few weeks yet and I have a number of options.
I presume in all cases it is best to install W98 first on a different partition from peppermint 3?
If you are willing to re-install Win98 then you could just clone the the W98/Peppermint disk onto the Mint HDD.
Then make sure Peppermint is working in the new setup. When happy then re-install Win98 (overwrite the original install)
onto the new HDD (same partition as before). This will overwrite the boot loader. You will only able to boot into Win98. 
To repair the boot loader you will need to boot with a LiveCD and repair grub from Peppermint.
(In not so many steps) 
If on the other hand, you’re going to reinstall BOTH from scratch (possibly going with Peppermint 4 instead of 3) … then YES, install Win98 first.
Thanks to all I think I am going to do a clean install and copy any saved games over. Will stick with peppermint 3 as it is a LT release…not reinstalling every year,