Problems on Yahoo Messenger FOR MAC OS X:How do I upgrade it???Please,HELP!?

I am now using a really really old yahoo messenger(not including Avatars,Environment,Audibles,Mic-talk,Ca… computer-feature,etc),it's all so basic,and I can't even use MIC!I am using Apple Macintosh OS X,and I've tried downloading Yahoo Messenger Beta for Mac but after following the instructions which is to drag the icon to 'Application' folder,I can't open it after doing so.The icon appeared and is gone in my desktop(where there we can found icons like i-Cal,i-Chat,i-tunes,internet explorer,etc)it doesn't stay there and get opened....So,how do I have a BETTER version of YM???If what I have now is not too bad,I won't be asking for this,but it's really really OLD!I'm helpless..So how do I upgrade it?I really really really hope I can have a better version of it,even it's not the latest version...that's more than enough as long as I can talk using MIC and call-computer-feature at least.. Please help me..Or anyone know how to upgrade the features one by one...please,help..thanks,really..