Hi

Three generations of PC processor, now pretty much obsolete, the ancestors of Intel's Pentium. The 286 was the earliest processor able to run (just about) a version of Windows, although the 386 was really the minimum to run it properly. The 486 was the earliest processor able to run Windows 95 - just about. Machines of this vintage cannot run modern versions of Windows at all, but many are still in use as basic word-processors or where a dedicated machine is required which doesn't need to be powerful.