You do not need to convert ._eml files to .eml files. The first is just a renamed variant of the original email message, usually to prevent some sort of error or bypass some email attachment filters. Just rename it back to restore the associations.
Convert Windows Mail Live email to Email message.
We found one software available in the database for this conversion.
Microsoft Windows software - convert _eml to eml on Windows
E-mail client for Microsoft Windows
Convert from _eml file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.