Our machine is six years old, now faulty, and the vendor says it is discontinued. Is replacing the whole system the only option?

No, and usually the whole system is not needed. First, consumable parts are replaceable: SSD, RAM, CMOS battery, fan (if any), power supply and cables. Many failures after 5–7 years are simply a worn SSD or a flat CMOS battery losing the BIOS configuration — replace it and the machine runs on. Second, if the board itself has failed: industrial computers have long life cycles and vendors publish end-of-life notices (EOL/PCN) with an equivalent replacement model. We look up that replacement and compare the points that usually cause trouble in a swap: input voltage range, dimensions and mounting holes, number and numbering of COM ports, and whether your operating system still has drivers. Third, if the old application only runs on an old operating system: tell us up front so we can pick a machine with drivers for it, or plan a virtual machine. This is what most often makes a replacement project drag on. Send us the old model number and a photo of the port side, and we will propose an equivalent and spell out the differences to handle.