It seems like, problem with your BB Desktop manger Installation it doesn't recognizes BB when you connecting it. Try these:
1. Uninstall BB Desktop manager and other BB related programs. Install all updates. DO NOT CONNECT YOU BB YET!!! Make sure Cable you use is one that came with BB.
2.Charge your BB in full, Before connecting BB to the PC( assume you reinstalled Desktop manager after rebooting a PC) remove battery from BB for 5 sec and then install it back it will restart you BB, it also can be done by Pressing ALT+RIGHTSHIFT+DEL.Original cable is a must.Another Hint( old Software not always removed comletly from pc and have old regestry files sitting there). Get free programm CCleaner to clean your files and regestry, also manualy go to My computer>Program Files and Manualy delete old undeleted BB related programs. After cleaning your regestry and following this steps I hope you will be allright.Ccleaner is free and very good programm.
Hope it will help you!!!