Hi, welcome to the forum!
Screenshots would definitely be helpful. Unless you have some ultra rate artists or homemade compilations, it is not normal for mb not to be able to find info (I am assuming you mean in the CD-ripping screen)
Be sure to take a look at the Tag inspector (available in the Tag editing screen) when you are having trouble. That will show you the raw tag info in a file.
Most of the problems you describe are not bringing up any ideas for me yet, but the multiple files showing up might be related to embedded cue sheets, and problems accessing info online could be related to a problem with security software. If you white list mb or turn off your security software, does that help?