Can't login to my gmail, can do pretty much nothing .. please help me
Clear the cache and the cookies from sites that cause problems.
"Clear the Cache":
"Remove Cookies" from sites causing problems:
If clearing cookies doesn't work then it is possible that the cookies.sqlite file that stores the cookies is corrupted.
Rename (or delete) cookies.sqlite (cookies.sqlite.old) and delete other present cookie files like cookies.sqlite-journal in the Firefox Profile Folder in case the file cookies.sqlite got corrupted.