Follow the given steps to change the yahoo messenger registry value :
- Click Start button and type regedit in Run option then press Enter for next.
- Here locate the location to :
- HKEY_CURRENT_USER/Software/Yahoo/Pager/Test
- Here in right side panel, right click to create a new Dword value with name Plural and give it value 1.
- Now close the registry editor and restart your computer after any changes to go into effect.
- For signing in with new YAHOO ID open another messenger open as many messengers you need.
- If you want to disable the multiple messenger option then again open registry editor and change Plural value 1 to 0.