* Go to Start >> Run >>
* Type regedit >> press Enter
* Go to HKEY_CURRENT_USER >> Software >> Yahoo >> pager >> Test
* Then Right click on Test >> choose New >> Dword value.
* Rename it as ‘Plural’.
* Double click it >> assign a decimal value of 1.
* Close the registry and Restart yahoo messenger.
Hey Its All Done!! Now you can open multiple instances of yahoo messenger and login into each from different yahoo ID.