[tabtab]

It depends on how "computer" is defined. Being there is a wide range of mechanical devices that can count and/or "execute" formulas based on variables/parameters, the boundary is pretty fuzzy.

But "Turing Complete" is relatively clear cut. To make a long story short, it means it has the equivalent of IF statements and loops. The first such device proposed is probably one of Charles Babbage's devices, which he was never able to complete. The first known to be actually completed is the German electromechanical "Z3" by Konrad Zuse in the early 1940's. In theory you could run Windows programs on both devices; IF you have tons of patience, storage tape, and time. (And want to build an x86 emulator for them.)

[fermienrico]

Thanks for the insight. I think it is the concept that is so very appealing that if a machine is turing complete, it can solve any problem that any other turing machine can solve (just takes longer or needs more memory).

It elevates the machine to a common capability level that can solve any computable problem. Therefore, it is important to understand turing completeness.