IDA for Windows just means that it runs on Windows, you can still work with several different formats. MZ and COM are both in the list of those supported formats.
i need to trace exe program which runs on dos, i thought, that whith ida i can do it like in windows i can trace projects in vc++ F5 or F10 step mode. if i'll run ida on windows i get only assembler code of my binary file? or not?