Try Google the next time round. Here's a possible solution
regarding your issue.
Problem:
Write-protection tab went nutz.
Solution:
put a piece of tape over the switch on the sd card and it will
work.
Explaination:
An SD interface includes a tiny copper finger which the
write-enabling tab of an inserted SD card depresses onto another
copper contact thus closing the circuit which enables the writing
to take place. I suspect that that tab inside your SD reader is
broken, bent, or somehow inoperable.
Source:
http://www.tomshardware.com/forum/11414-2-card-reader-card-write-protected