Mail "reply keys don't work right

I haven't seen this problem discussed anywhere, but it has me defeated. I have an iMac, OS 10.6.7, with Mail 4.5. Starting a few days ago when I try to reply to an email, I first get a copy to write my reply on, but the "send" button is the double arrow reply to all button, not the reply to sender button. When I hit that button it changes to reply to sender, when I hit it it changes to reply to all, and round and round. But, if I save the message as a draft, then try to send the draft copy it works normally. It also works normally for original emails and forwards.

I did a safe start, holding down the shift key while starting. Then I did a normal restart, and that did nothing. I have two email accounts, and this happens with both (Yahoo and GMX) If I reply through the Yahoo Mail webpage it works normally.

This is my wife's computer, so my name is mud if I can't fix this!

Ok, right click anywhere near the reply all button and choose "Customize Toolbar"
Find and drag the reply button back beside the others and see if that fixes it.

YIpee!!! Now, I'm a hero. it worked beautfully, and I didn't realize that function even existed. Thank you very much.

Does this mean the buttons can be accidentally dragged off the tool bar like the icons on the Dock can? That would explain how the send button disappeared so suddenly. Since I don't normally use that computer - mine is an older model - I didn't recognize that the problem was a missing send button, not a mis-programmed reply button.

Yes, if you hold down command and drag then out of that area they will "poof" like dock icons.