Are you using Windows 7?
If so....
Go to Start > Right clock on my computer and choose Properties.
On the left of the screen choose Device Manager
On the bottom of the list should be Universal Serial Bus Controllers
Right click on all of them and choose properties.
go to the Driver tab on the top of the window
Click on uninstall.
Repeat on all the items under Universal Serial Bus Controllers.
Restart your computer. Windows will automatically reinstall the drivers.
If that doesn't work go to HP's support website and download the chipset drivers for your specific computer.