Step 1... find the person that designed the ID column... take him/her to dinner... feed him/her 2 pound porkchops... at point blank range with a sling shot!
Ok... having said that, I feel better.
You need to give us a bit more information... is the format of the IDs consistently in the form of AAANNNN? Are they, in fact, unique?
And, if you want a better answer quicker, please read and heed the advice given in the article at the following URL...
http://qa.sqlservercentral.com/articles/Best+Practices/61537/