I have a brand new Inspiron 9100. In fact this is my second one in a month. The first was replaced because the mother board went out. Anyway, after upgrading from XP home to XP PRO sp1. I cannot plug a USB mouse into the laptop.  I plug the usb mouse (MS Optical MOUSE) in while booting the light comes on but as soon as you get to the windows xp boot screen it goes out. The mouse does not work at all and the light does not come on. If i unplug from the USB Port and plug it back in. Windows does not recognize it. The mouse works on my other laptops. I noticed quite a few people have the same problem but no solutions. Can anyone help.