failed to login bad login 1.6.4 bug

So i tryed to join multiple 1.6.4 servers and everytime i tryed i got "Failed to login: Bad login." So i closed that minecraft and relaunched a new one. Again i got "Failed to login: Bad login." So i edited my profile into 1.7.2 and logged in and off and edited it back into 1.6.4 and tryed to join the servers and again "Failedto login: Bad login". Is there something i have to edit in my profile or do i have to redownload from minecrfat.net? Or is it a bug with the Minecraft.net website? please help i miss my friends