File rename program

I have several folder that hold hundreds of images that I need renamed. I need to rename each file in a designated folder with a text word and a number. The number should start with a number I choose and increase as the files are renamed. example: rdj_1 rdj_2 rdj_3 ect. I don't care the language that is used as long as it works!! Simplicity is the key because I do not want to pay a lot for this. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Installation package that will install the software (in ready-to-run condition) on the platform(s) specified in this bid request. 3) Complete ownership and distribution copyrights to all work purchased. ## Platform Windows XP Professional