I just found this forum. This is an awesome site!
I have an Acer Aspire 3100 with Windows XP Home Edition Ver 2002 (Service Pack 3) installed. When any USB devices is plugged in, the screen freezes (computer freezes). All my USB works fine in another computer. I have checked Device Manager and all USB ports indicate that is is "working properly". Could someone direct me to resolve this problem? Thanks for your help.

I take it you have not been playing in the BIOS area of your machine!
If you have please return there and return the settings to defaults for now.

If not there are three possible options for you

1. Via the control panel uninstall all the relevant components for the USB BUS and Hubs and restart you machine - you may need to uninstall some of them a couple of times.
2. Disable the USB in the BIOS and use an external USB card which should fit into the expansion slot on your laptop, mind you I have seen quite a few "cheaper" machines recently which dont have expansion ports. If you decide to follow this route you will need to ensure you either know the type of expansion slot you have or take the laptop with you when you go to buy the replacement and seek the advice of a local computer shop, dont bother with the local PC World as they will probably not know what your talking about and try and sell you a replacement machine instead.
3. Look into the USB ports and check that there are no hairs or other nasties lurking within which could be "shorting" the electrical current.