I have one very strange problem and i need help. I Have one mountain bike my friend gave to me. I true the rear wheel i replace the front wheel is was bent. I install v brakes i replace cable in the RD is shift okay. FD i put one old i had i put new cable but The FD not moving at all. The shifter move the cable when is loose but when i attach the cable to the FD screw the FD not move at all. What is can be wrong.

Did you anchor the cable housing properly?

Not enough information.

Could be the derailleur cable was installed too loose, or with the shifter in the wrong gear/position when the cable was pulled tight. What gear did you have the shifter in when you installed and tensioned the front derailleur cable?

Or, the front derailleur and/or the shifter could be defective.

Or, the front derailleur could be the wrong type/pull. Some front derailleurs are designed to pull the cable up and are used for top ruted cables. Other front derailleurs are designed for pull down, and are used with cables that are routed down by the bottom bracket. Other front derailleurs can be used for top pull or bottom pull, but you must route the cable correct for it to work.

Thank you for your answers. Finally i found the problem is was the cable is has rust i put new cable and the problem is fixed.