Turn on tabbed yahoo messenger
Turn off tabbed yahoo messenger
Download and run the first file when you want to turn on tabbed messenger and use the second file when you want to return back to the normal mode.
So whats inside the reg files. Actually nothing much just a registry entry needs to be added that tells the IM to use tabs for conversations.
[HKEY_CURRENT_USER\Software\Yahoo\pager]To go back to the normal mode change the 00000001 to 00000000. The code is there if you know how to tinker with the registry for most other people download and and run the reg files and you won't have to worry about messing around with the registry.