Dual plug (AT or ATX) were available until very recently in "corner shop" outlets. Many users like me have dumped just what you wanted.
Failing a thorough scrounge around (there may be others on this forum that would give you their "junk" in return for the postage), nothing is impossible to someone with time and a small soldering iron.
Stating the obvious, you will have to check that you finish the plug adaptation so that the correct volts and amps are available where they should be and nowhere else.
Thank you: this is precisely what I needed to know.
The existing case has an on/off switch and a reset button. The on/off has four push-on connectors. It seems that I am not able to use the ATX PSU in the existing case because it will not interface with the switch. Hence the query about using a new case.
Where can I find info about wiring the switch to make it ATX compatible?
I think you will be a lot better off buying a new case which are almost as cheap as psu's if you look in the right place than to start messing around switches etc....
As for that case its advanced to what you need. I think that AT PSUs are all 200w so you would not need a 350w although the power could do no harm.
I think that click here would be a cheap easy and affective fix. Also only £21.44 including P&P & VAT.
BUT be carefully where you take out of where especially if you have no manual. Writing down and taking pix on digi cam (if u have a digi cam) would be a VERY good idea. Otherwise when you come to think where did this come from / where does it go you might have a big problem.
Hope this helps
Also i also have spare AT PSU if you would Rather purchase that off me for a very low fee.