most likely all the usable raw materials would have been scavenged, or melted, or ruined by the weather, or lacking any of the sundry bits of support liquids/so

most likely all the usable raw materials would have been scavenged, or melted, or ruined by the weather, or lacking any of the sundry bits of support liquids/solvents/grease necessary to make it run say you do find a working factory with everything in it only waiting to be turned on it'll likely have manuals in some file cabinet and won't need an external computer But yea, it's trivial to paint a scenario that makes a working computer useless, however it'll be difficult to keep one running. So, best of luck!