Simple steps :
create one notepad file with any name like pen.reg or pencil.reg and Paste the below code into notepad

REGEDIT4
[HKEY_CURRENT_USER\Software\yahoo\pager\Test]
"Plural"=dword:00000001

Double click on .reg file message window appear “Are you sure you want to add the information in to the registry" - select "Yes".

double click on yahoo icon again and again… with other ID....