Funny, had a Win98SE machine that typically ran for months at a time, running a single telephone logging application for a PBX. Only reason it did not get more was either hardware failure, or UPS running out of power due to long power outages, or somebody pulling the plug on it. Was scrapped when the PBX was upgraded around 5 years ago, and the new Samsung PBX is a lot less reliable than that Win98 PC was.
I did have a lot of spares for it, spare formatted cloned drives, spare power supplies, spare motherboards and even spare PS/2 mice and PS/2 keyboards. Needed a serial port to talk to the PBX, and a parallel port for the software dongle, but the printer was upgraded to USB later on, even though I could use a HP printer and talk HPGL5 over the network to it, as all networked HP printers will support this. It thought the printer was a HP4MV, and did not care any further.