my email account is very slow in general. how do i fix that?

You should talk to your email provider.

having trouble accessing my emails residing in inbox folders i created.

Please explain what 'having trouble' means in more detail.

cannot find "reply" tab after opening an email

Please provide a screenshot. http://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem

my email provider is thunderbird. i thought i was in the thunderbird support forum.

my email provider is thunderbird.

Thunderbird is an email client you use to access your mail from an account you set up with an email provider, e.g. like Gmail or Yahoo. Neither Thunderbird nor Mozilla is your email provider.

i thought i was in the thunderbird support forum.

You are.

i have 2 gmail accounts one using thunderbird and the other one which is working fine.

Please answer all questions. https://support.mozilla.org/en-US/questions/1116918#answer-862969

In addition:

my email account is very slow in general.

Please explain 'slow' in more detail.

so, now i'm narrowing down my problem. i have various inbox folders and usually i can click on one and my list of emails pop right up. now when i try, it either freezes on the folder not allowing me to move around or even leave the folder.

Start Thunderbird in safe mode. https://support.mozilla.org/en-US/kb/safe-mode-thunderbird Uninstall Lightning via the Add-Ons Manager. Restart Thunderbird. Re-install Lightning in case it's needed.