The MicroSoft Access downloadable databases have an .accdb extension, which can be opened with MicroSoft Access 2007*, 2010, 2013 or 2016. You may want to check with your institution's ITS support about getting a more recent version of MS Access for your PC if you are unable to open a downloadable database.
*Note that MicroSoft Access 2007 may need additional MicroSoft Access drivers installed for reading .accdb files.