Usb not detected - please help :(

Currently have a laptop xp home sp2 and having a problem with my usb, only 1port is working.

under device manager, it shows : "this device is working properly" for ALL ports,although the other 2x ports does not detect when a usb drive is inserted.

device manger > universal serial bus controllers (shows the following)
>sis 7001 pci to usb open host controller ...(this is the drive that does not detect the drive when inserted)
>sis 7001 pci to usb open host controller ...(this is the drive that does not detect the drive when inserted)
>sis pci to usb enhanced host controller ...(this is the port that detects the usb drive when inserted)

please help