It looks like you are at the "this probably doesn't have anything to do with anything, but it includes the word "Mouse" and I'm desperate stage.
So.....
http://www.winguides.com/registry/display.php/1268/
Using BOOT.INI Startup Switches (Windows NT/2000/XP)
/NOSERIALMICE=[COMx | COMx,y,z...] - Disables serial mouse detection of the specified COM port(s). Use this switch if you have a component other than a mouse attached to a serial port during the startup sequence. If you use /NOSERIALMICE without specifying a COM port, serial mouse detection is disabled on all COM ports.
Same thing here, but gives some more detail, http://www.geocities.com/csc_online/os/winnt/ and specifically mentions Logitech Mouseware and a Marble mouse.
-And then see if the problem goes away when you use the mouse with/without the PS/2 adapter.
-On the other hand if that switch is already there, try taking it out. Also the /FASTDETECT switch skips serial device detection, so if that is there try taking that out as well.
-You also might want to try the playing around with the /SAFEBOOT switch.
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[Since you reformated when you reinstalled this probably is probably isn't a Ghost problem either, but......]
"23. Uninstall ghost devices or services in Win2k/XP
When one removes hardware or a service, then sometimes Windows still thinks that the hardware or service exists and they roam about as ghost devices in the Device Manager. Ghost devices can cause slow boot and other erratic behavior because Windows tries to communicate with a device which isn't there.
To make sure that no ghost devices exists, add the following STRING values to the registry (They will become enviroment variables):
[HKEY_LOCAL_MACHINE \SYSTEM \CurrentControlSet \Control \Session Manager \Environment]
DEVMGR_SHOW_DETAILS = "1"
DEVMGR_SHOW_NONPRESENT_DEVICES = "1"
Then start the Device Manager and select "View" in the menu and select "Show Hidden Devices". Now it should show all devices registered in your system, making it possible to remove any ghosts which shouldn't be there."
http://snakefoot.fateback.com/tweak/winnt/tips.html
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Good Luck!
It looks like you can use as much as you can get. 😀