How can I sign in multiple account on yahoo?

Sometime it is need to sign in multiple account on yahoo at a time. But normally it is not possible to sign in multiple account at a time. Now what can you do? Suppose you and your friend want to chat on yahoo at a time. But you have only one computer. At this moment what can you do?
Today I am talking about a way to sign in multiple yahoo account. It is not any hard work to sign in multiple account instantly. For do it follow this:

• First of all install yahoo messenger for chat. If the software of yahoo messenger is not in collection then click here.
• Click on start button and go to Run. Write down "Regedit" and click on Ok. Then the application of Registry Editor will be opened.
• After open the program of Registry Editor go to HKEY_CURRENT_USER, Software, Yahoo, pager, Test .
• Now right click on the button of Test and click on New-DWORD value.
• Rename this new DWORD value to "plural".
• Double click on it. And type 1 in the box of value data and press ok.
• Now open the yahoo messenger, give your id and password for sign in. After sign in an account again open this program. And now give the id and password of another account for sign in.

I hope all can understand about sign in multiple account on yahoo.Thank you for see it. If you fail to understand anything about it then inform me. I will try my most for solve it.