I had a text file that was actually in two different versions on two different computers. After switching the version from one to the other, believing the first one had more on it, I realized the version I overwrote actually had different information on it. Is there anything I can to retrieve the old file? Thanks.

It's SOP to periodically backup your data files, either manually or automatically with appropriate software. If you are following this practice you can try retrieving a previous version of the desired file from your backups.

If you are not doing the above, some text editing/word processing programs (i.e. Word) can be configured to backup/save previous versions of files edited with the program. Check the program you used to edit the document to see if it has this feature and if it has indeed saved the version you need. These files might also exist in temp files created by some programs.

If neither of the above works, you can try some file-recovery programs like HandyRecovery and PC Inspector File Recovery.