Too many failed logins on Minecraft?

I keep on getting "Failed login" or "too many failed logins". I got Minecraft from my friend for free. My account works on Minecraft.net. How can I Fix it. I don't have Admin privileges and I have the Norton Family(if you know what that is). How can I fix it?

Go to your.minecraft folder (User/AppData/Roaming/.minecraft) open that up, then go to the file that says last login, and delete it, then close the.minecraft folder, run minecraft, it will take you to the login screen, type in your info, and you should be good to go.
OR
Deleting the META-INF folder in the minecraft/bin.
OR
Waiting a time period of 24 hours will effectively decrease the login attempts to 0. This will be fixed if the error message is legitimate.
OR
Clean installing your Minecraft will erase player data and might solve the issue. You may want to back up your saves and texture packs before doing this. To do this, simply delete your.minecraft folder and launch the Minecraft downloader/launcher.
OR
If you are playing 1.9 pre release, you may be suffering from client bugs. Downgrading to 1.8 will solve this. To downgrade: follow the same steps as in solution 2, but redownload the launcher from minecraft.net