problem with rear usb's

[offroader]

Hi just wondered if anyone had any ideas.
I have a packard bell imedia 1529 pentium 4 3.06GHZ 1.00GB ram running on xp home .
The problem is after 8 months of trouble free usage the usb's on the rear of the pc have packed up . However the 2 usb's on the front are working fine so at the moment i am using a powered hub plugged into the front to power my equipement. There are 5 usb's on the rear.

Can anyone suggest what it may be

Many thanks in advance

 

[offroader]

Thanks for the replies.
I had the webcam , digital camera , mobile phone plugged into them.
also the usb's are not via a metal plate

 

[offroader]

Forgot the about the printer that was also plugged into it.

I am now using them all through the front usb's