To the OP:
As a further point, the N810 (and many handheld devices) use an ARM-based processor, as opposed to x86-based, like most desktop/laptop computers, so unless a program has been designed for mobile devices that use ARM, it definitely won't work. (The program's binary representation would be in the wrong "language" for the processor.) The exception to this is Open Source programs, many of which can simply be recompiled to run on a different processor architecture. With proprietary programs, this is not an option unless the vendor decides to do it themselves... which they generally don't. If you find an Open Source program that is available for the Linux desktop, but not for Maemo, you can always put a polite note on the forums asking if someone will port it (if it's particularly complicated, offering a small cash incentive can make it quicker :P).