maybe its useful to use this constring:
string conStr = "Provider=Microsoft.ACE.Oledb.14.0;Data Source=Database1.accdb; [Some Other Options=etc.;]";
for Office 2010
string conStr = "Provider=Microsoft.ACE.Oledb.15.0;Data Source=Database1.accdb; [Some Other Options=etc.;]";
for Office 2013
i know that its could happen if you use windows 7 (64 bit) and office 2010 (for example),
that you need to install the "2010 office system driver data connectivity components" (<-google for it - 32 or 64 bit available) too.
but i didn't find actually such "office components" for 2013, so perhaps the "old" 2010 components works also on 2013.
by the way, as far as i know the JET-engine is no more supported since/for office 2007 ;)