Laptop freezes when USB ports used

Have you run a full scan for viruses?
In hardware properties are there any conflicts and does it say "this device is working properly" when looking at the usb ports?

I'd be interested to know what version of windows you are using. If you're running win98 or ME it could be conflicting IRQs.  Check your bios settings to see if you can reassign IRQ values so that nothing is being shared.  If you're running 2000 or XP this won't matter.  
I had a pc running xp that I built about a year ago that was giving me similar problems.   that turned out to be a ground issue though and I don't think that is your problem in this case.

Erik

Had this problem many times, very simple solution:

1. Go into Device Manager and expand the "Universal Serial Bus Controllers" group.
2. Uninstall every device listed under this group (right click on device, left click uninstall)
3. Be sure all USB devices are unplugged!! *THIS IS KEY*
4. Restart Computer
5. Upon restart the computer will recognize all the devices and install them.
6. Plug in a device and see if it works.

Hope this helps!

Tried  uninstalling and reinstalling drivers.. but made no difference

There are no conflicts in device Manager

Running XP

and have checked for viruses

could it be the actual board?

Doesn't matter if it says there are conflicts or not....just do the procedure.  Its recognizing generic drivers when they don't work.

sorry i worded my reply badly!

I checked for conflicts as 2  answers suggested and there were none THEN I uninstalled all the USB drivers and  shut down laptop.. when i poswered up it installed new hardware.. but the mouse  still froze  the internet connection after a short while