Ok lets roll back some dude, What was everything you have installed from this cd.
I would uninstall everything you install and go one step at time.
So you formated computer then get all the windows updates installed.
Gonna be awhile but worth it and alot of reboots.
Once you have got all windows updates computer right then install ad-ware and run full spyware scan, also install spyboat and run full scan.
Then install your yahoo messager if it works great, Then install these cd programs one at time shut down yahoo messager before you install, once installed start yahoo messager.
That way you see if it was that program you just install thats making yahoo messager not working right.
If everything from cd is install and you got all windows updates and you also run spyware scan all this from a fresh install of windows I can't see what the problem is.