Strange UNO USB problem

I have for about a week a UNO smd-edition. Inside the Arduino IDE it works fine but when i tried to connect to it by a terminal is wont work.
Also with a program that writes something to the UNO says that the com port doesnt response.
Mine whas connected to Com5, but even changing it to another port doesnt help.

Anny suggestions?

Wrong COM port perhaps?
Post the code

Sir can you help me to Troubleshoot my UNO ?
My uno cant get detect in Device manager i think the Firmware of USB IC got problem pls help .

I have tried the solution given here but the solution is for another vision of UNO and i cant take the UNO in DFU mode .. Thanks .

HugoPT:
Wrong COM port perhaps?
Post the code

It has nothing to do with the Arduino code.
Seems to be a Windows7 USB problem.