Excel 2007 : Reference Cell is blank, want Vlookup to show either blank or zero

Hi,

I've tried the following formulas and it either doesn't work or show error message of too many arguments.

=IF(VLOOKUP(A7,TEVA!$C$4:$O$352,13,FALSE)="","",VLOOKUP(A7,TEVA!$C$4:$O$352,13,FALSE))

Formula still shows N/A when "a7" is blank

I've tried

=IF(INSA(VLOOKUP(A7,TEVA!$C$4:$O$352,13,FALSE),0,VLOOKUP(A7,TEVA!$C$4:$O$352,13,FALSE))

formula shows too many argument error message.

I appreciate any help.

Thank you,