I noticed that you said that you switch to the normal "green" plug mouse.
That is a PS2 mouse, not a serial mouse. the serial has the D shaped 9 pin
connector while the PS2 mouse has the green round connector.
The motherboard has to detect the PS2 mouse on boot for it to be recognized
by Windows. Some computers require you to power off, not just reboot to
pick up the mouse.
If you power off the computer and turn it on with the PS2 mouse still
plugged into the PS2 port, then:
1. Your mouse could be dead.
2. Your computer's bios my have the PS2 port for the mouse shut off
(Different on every computer)
3. If you are using the PS2 to Serial adapter, the adapter could either be
the wrong one or broken. I have several PS2 MS Mouses (Mice? Meeses??,
whatever) and sometimes I had mixed up the PS2 to serial adapters that came
with them. The different models are not interchangable.