This does not look ok:
If File.Exists(t & "C:\Users\Windows 7 User\Desktop\bookings.txt")
it should be something like:
If File.Exists("C:\Users\Windows 7 User\Desktop\bookings" & t & ".txt")
And even better:
If File.Exists(My.Computer.FileSystem.SpecialDirectories.Desktop &
"\bookings" & t & ".txt")