HowToInfa : Undocked and now can not dock

I got the solution from ITTOOLBOX.
docking problems with powercenter designer

And it is:-
1. close all Informatica instances like Designer , Workflow manager and monitor
2. backup the registry
3. go to HKEY_CURRENT_USER
4. go to SOFTWARE --> Informatica --> POWERMART CLIENT TOOLS --> (whichever version you are using) my case 7.1 -->Designer/Workflow Monitor/WFManager --> Toolbars 7.1
5. rename the folder Tolbars 7.1 to anything like toolbars 7.1_old
6. save and exit the registry editor
7. Restart Informatica Designer/WFManager/WFMonitor