You may know that you can login one yahoo id to chat from a single PC. So hare is a tweak to over come this. Using this you can run multiple yahoo messenger instances in one PC and can login different yahoo ids on each

Here we go (Please confirm that yahoo Messenger is closed)For more yahoo messenger tricks check this

• Open registry Editor (Start=>Run Type REGEDIT press OK)
• Go to HKEY_CURRENT_USER\Software\yahoo\pager\Test
• Check for a key named "Plural"
• If it is not there create one (Right Click => New => DWORD) and Rename it to "Plural" (with out quotes)
• Change the value to 1
• Close Registry editor and open Yahoo messenger
• Now when you open each time using yahoo messenger will open different yahoo messenger windows. and you can login different ids on different windows.

For this tweak you can download this file and can run that.

For more Yahoo messenger tricks check this link Yahoo Messenger Tips and tricks