Wireless IntelliMouse Explorer 2.0 become defect

I am using a Wireless IntelliMouse Explorer 2.0/Driver IntelliPoint
5.0 on my iMac G4 OS 10.3.9. Till few days, I didn't have any trouble,
suddenly some buttons was not responding anymore. I thought on some
corrupt prefs. and put them in basket. At the restart, the mouse was
fuctionning but same buttons still not responding. I try to find an
Update Driver on Mactopia but couldn't find anything related to my
IntelliMouse Explorer 2.0.
I decide to uninstall IntelliMouse 5.0 and (re)install it. Same !
At this point, I put all files (I think) use by Wireless IntelliMouse
Explorer 2.0 in a folder on my desktop (Microsoft Mouse App.,
com.microsoft.mouse.global.pref, com.microsoft.mouse.items folder and
com.microsoft.mouse.pref) and make a new install from the Microsoft
CD.
Surprise... the CD have installed IntelliPoint 5.0 but not Microsoft
Mouse Software: Hoe to configure the mouse ?
Since that, I am looking everywhere in Microsoft or Mactopia to find
the Microsoft Mouse Software and an Update Driver without succes.
Where to get it or what should I do ?