I'm having a few issues with Windows Media Player that is really starting to piss me off.

I've got all my music files in one folder (like most people) but WMP seems to separate some of these files from a single file into multiple files. How can I stop this from happening?

i had this also happen, and for mine it was because there was a hidden "album artist" field that showed now up in the normal wmp tag editor. i had to use third-party tag editor to see and delete the duplicate album artist spot. i used dbpoweramp, if that help.
sometimes also you can just click\drag several files to the same album, for it to prompt if you want to combine.

Is this a freeware program or do you have to buy it?

I'm having a few issues with Windows Media Player that is really starting to piss me off.

I've got all my music files in one folder (like most people) but WMP seems to separate some of these files from a single file into multiple files. How can I stop this from happening?

Hmmm... Windows Media Player. There's your problem.

I'm open to other ideas if you have them as long as they don't start with an i..like iTunes.

dbpoweramp is not official free, but can be found free for certain sites...
you could use also some program like mp3tag or tagscan, that are free, which may show issue with tag (or could remove all tag and replace, to be sure).

for player, some member here use foobar, and say it good. i use jriver media center, since it has library, but is flexible with filetype\format.

Good tip there. Tag Scanner is a great little (freeware) program.

The Ultimate TagScanner: News (http://www.xdlab.ru/en/)

Latest download links are on the right side under "News".

One can quickly check the tags in the columns and make changes to ensure tracks are grouped correctly - some mp3 players group and order by tag, not by filename.

I don't know about the other programs the above users have suggested but I personally use Tag&Rename for my tag editting. It's very difficult sorting out music correctly, even my own playlist is a huge bother. What to do though......*sigh*