How Can I solve the NO DEVICES FOUND Press 'M' and '+' to add

[Bgfminer]

Hello. my system has not graphical card. my system works only with cpu pentiom(R) Doal core CPU E5700 @3.00GH.I install BGFminer 5.5. I open  the BGFminer.exe file.also I have join in F2pool website.in my account there are in part of the Workers page  the Pool 1 URL, and the worker and the password information.When I open the BGFminer.exe file I add the Pool 1 URL, and the worker and the password information  and I press inter button.and after I get the NO DEVICES FOUND  Press 'M' and '+' to add.
How Can I to solve this problem? I searched in google very much but yet I do not understand.
Please tell me step by step what should I do?
thanks.