Possibly you can connect with 'localhost' using '.' and 'integrated security = true' see connectionstrings.com:
Connection strings for SQL Server[
^]
Something like:
1)
Trusted Connection[
^]
2) Or try using :
Data Source=.;Initial Catalog=myDataBase;Integrated Security=true;
Remember, in all of the above cases you can access the database but can not get advantage of 'sa' user rights.
Hope it helps!