Here are simple steps you can follow to run multiple yahoo messengers on your PC.
Step 1- Go to Start > Run > type regedit and press enter.
Step 2 – Go to HKEY_CURRENT_USER > Software > Yahoo > pager > Test
Step 3 – On the right pane > right-click and choose new Dword value .
Step 4 – Rename it as Plural.
Step 5 – Double click and assign a decimal value of 1.
Step 6 – Now close registry and restart yahoo messenger.
Step 7 – For signing in with new id open another messenger .