I would keep an int variable in the Application Settings, which I would use and increment every time I needed to backup. Something like this (where
Properties.Settings.Default.fileCount
is the variable stored in Application Settings
int currentFileNumber = Properties.Settings.Default.fileCount;
string newFileName = String.Format("YourFileName{0}.mdb", currentFileNumber + 1);
File.Copy(string.Format("YourFileName{0}.mdb", currentFileNumber), string.Format("YourFileName{0}.mdb", currentFileNumber + 1));
Properties.Settings.Default.fileCount = currentFileNumber + 1;
Properties.Settings.Default.Save();
Hope this helps