Please notice this subject was already posted in the thread: http://communities.intel.com/thread/31090
As recommended earlier you may want to contact the computer manufacturer as the cause might be related to integration or a defective adapter they may need to replace.
Please keep in mind the Intel® Centrino Advanced-N 6235 wireless adapter was included as part of an OEM system, so the warranty is provided by the computer manufacturer due to an agreement with Intel®. The same applies to other OEM components provided by Intel® such as chipsets, SSDs or processors.