Open old files or files which you can open. Delete everything from them and save them as template file under a known location. No map the ne location under System Options > File Location > Document Template. If you have one of each type (i.e. part, assembly and drawing template) then you can set the System Options > Default Templates also OR can pick from multiple template as desired.
These are the two default locations:
C:\Program Files\SOLIDWORKS CORP\SOLIDWORKS\lang\english\Tutorial