Private Sub Command1_Click() 

For varpart = 54000  to 55120
   strpart = CStr(varpart) 
   strname = "c:\A" & strpart & ".min" 
   intreal = freefile
   Open strname For append As #intreal 
   Close intreal
Loop 
Close

End Sub 


Alternative way with dir function...

fname = Dir("c:\*.min")
do while fname > ""
   intreal = freefile
   Open "c:\" & fname For append As #intreal 
   Close intreal
   fname = Dir
Loop 
Close