Kindda strange problem. Was making a few modifications to the comments.module file so it would display "Say something!" above the comment textarea instead of "comment". I changed this text a bunch of times and saved without any problem. When I was satisfied with my text, I saved and refreshed the page then I got logged out from my site on localhost. I can't sign into the site. But when I type the wrong user/password it let's me know that my user/password is wrong.
I refreshed my 2 other browsers I was testing on (safari and opera) and those users got logged out too. The safari and opera users were normal users while firefox was my admin account. I've tried a bunch of things even tried to revert to a backup of the site(files and DB) that are 1 month old, but I still have this problem even though just 24 hours ago I was logging in/out... refreshing at will without any problems.
I've cleared browser cache, cookies... even tried just emptying the sessions and cache table in the DB but nothing works. Even tried from another computer to access this localhost but they also have the same problem. I've repair all DB tables multiple times. Changed the admin passwords directly from DB too.
Maybe worth noting is I have a phpbb installation attached. The user gets logged into my phpbb forum but not the drupal site. I dont think phpbb is the problem since I haven't touched it in 3 months plus tested it today and didnt have any problems.
Something I came across for the first time was the following error when i tried to create a new account. I can't even login to disable modules to see if it's the captcha module with the problem.
"Cookies should be enabled in your browser for CAPTCHA validation."
I honestly dont know how this problem came about since the only files I've touched in the last 3 weeks are css files and the comment.module just this morning(using an older backup of the file doesnt work).
I appreciate all the help you guys can give. Just let me know if you need anymore info.