Product Key not working

I installed SharePoint Server 2013 trial 

on Windows server 2012 

then I uninstalled it for some errors happened. 

then I tried to Install it , it gave me this error message:

I read some links witch told me to remove the registry key  but it dose not work.

the key I use it the trial version key :

NQTMW-K63MQ-39G6H-B2CH9-FRDWJ

from ms site:

http://technet.microsoft.com/en-us/evalcenter/hh973397.aspx

thank u for help