In another change of strategy, Compaq Computer Corp said yesterday that it would sell and support systems configured with the Beta 3 of Microsoft Corp’s Windows 2000 operating system. Back in January, when Eckhard Pfeiffer was still CEO, the company told ComputerWire in no uncertain terms that it wouldn’t be selling systems with the beta saying that it didn’t believe in offering products before they are ready. Compaq says it will support Beta 3 on Deskpro, Armada, Prosignias, ProLiant and StorageWorks, and will pre-load it on certain Deskpro desktops.