```
String baseDirectory = @"F:\Backup";
String mdbSourceFilePath = @"D:\Db\abc.mdb";
String mdbTargetFileName = "abc.mdb";

String fullDirectory = Path.Combine(baseDirectory, DateTime.Today.ToString("dddd"));

if (!Directory.Exists(baseDirectory))
    Directory.CreateDirectory(baseDirectory);

if (!Directory.Exists(fullDirectory))
    Directory.CreateDirectory(fullDirectory);

String mdbTargetFilePath = Path.Combine(fullDirectory, mdbTargetFileName);
File.Copy(mdbSourceFilePath, mdbTargetFilePath);

```

This is for backup of database. If I click on backup button this is creating backup database but if I click it again is is not overwriting existing database. I want to replace the existing database.