Mercury 3000 and DSI 286 computer

I got a computer labeled Mercury 3000 and a computer labeled DSi 286 and two printers both of which function compact disc reader and 8 is what looks like a modem and two keyboards, neither of the computers seem to function properly, as in I have only gotten both of them to turn on once, and then give up on life. Even the printer covered in dirt that was sitting in a wet box for around 30-40 years still works, but the two computers don't. With the Mercury 3000 computer, I know what the main issue is, however, the DSI 286 looks pristine inside, yet I've sadly only been able to turn on once and yell at me.