Question: Wordperfect 5.1 (for DOS) doesn't work without modification under Vista. How can I get it to work (as well as possible) under Windows Vista?

Answer: 
**Run it inside [DOSBox](http://www.dosbox.com/).** That should solve your problems.

Their emulation is quiet decent, they have solved problems with EMS/DOS4GW/whatever etc.

I think it should run any DOS application pretty much OK.
Maybe DosBox does work. It works fine with most Dos Games and Programmes. It's free and still beeing improved <http://www.dosbox.com/>