How can i recover my files encrypted in windows xp?

I encrypted some files in windows Xp through "right click>properties>advanced>encrypt". Then during the time to format my XP i forgot to reclaim those files by decrypting and all and reinstalled Xp. Now i am not able to access my files, neither move nor copy or delete them. Please help me out i have tried the certificate thing and all. If you have some kind of software or anything then please tell me to reclaim the loss. if you know how to reclaim through the certificate thing then please give me step by step info how to do it? please help me out and i will choose it as the best answer..... please