In most cases simply disconnecting USB device shouldn't cause a problem, but sometimes it does, if you don't use "Safely Remove Hardware" icon from your taskbar. I assume, it may be a problem with a device like mouse, because Windows constantly interacts with mouse, and unless you use "Safely Remove Hardware", Windows is not aware, that you're about to disconnect your mouse.
What you may try is to go to Device Manager, uninstall your mouse, restart your laptop, and hopefully Windows will find it again.
As for your Add/Remove problem, you may try this:
http://support.microsoft.com/default.aspx?scid=kb;en-us;329891&Product=win2000It's listed as for Windows 2000, but all three mentioned files are the same in XP, so it should work.
If it doesn't, restart your laptop in Safe Mode, and see if your Add/Remove list will populate there.