I just moved my sites from one server to another last night.  As I have multiple installations of WordPress, I found that I was having trouble logging in to two of my installs.

You see, I would put in my log-in credentials and push the log in button, but the login screen would simply refresh — thereby not allowing me to access my dashboard.

The fix?  I deleted the php.ini file in the root folder where the files of my WordPress install lay.

Worked like a charm!  Now, I can log in!

So, if you have tried everything else — uploading fresh wordpress files, disabling your plugins and resetting your password, this solution might work for you.