Write-protection problem for any pen drive

Hi,

I have a peculiar problem, my laptop is saying "The disk is write-protected. Remove the write-portection or use another disk." for any pen drive connected, even new one dosen't work but were as the same works fine in other systems. This happend suddenly, what might be the problem. Can any one help me solving the problem without formatting the laptop. I am using Windows XP with SP3 and I have upto date Symatec Endpoint protection 11 antivirus running.