HigherGround: he probably wants the low-down. The low-down is:
PC software is always written for the x86 series of processors, and usually specifically for x86 processors running Windows. It will not run on any other kind of computer UNLESS that computer has what is known as an "emulator" for the x86 processor.
A while back you could purchase a Digital Alpha workstation (a RISC machine) that ran Windows NT 4.0. It came with an x86 emulator that would run most PC software for Windows on the Alpha workstation. On Linux, you can run a program called "WINE" which emulates the Windows environment (but doesn't need to emulate the x86 environment, as long as you're running on a PC).
So the answer is, YES, it can be done even without re-compiling if you use an emulator.
But without an emulator, all executables must be re-compiled on the architecture (processor/OS combination) you're running them on. This is obviously impossible if the architecture doesn't have the appropriate libraries available (such as Win32 libraries). That's why you won't see Microsoft Word for Solaris anytime soon. Unless it's emulated...