hi,
   i download your trial version of the cheque system.but asking username and password at the starting time.what is the username and password? i cant open the cheque software without giving the username and passwords.what i do next?

In ChequeSystem, there should be no such dialog "Username and Password".
Would you make a sceen capture to us? And let us check for you.
Or you can uninstall the current copy and perform installation again.

And, in another software ChequePrinting.net, it has such dialog.
The default username and password is
Username: admin
Password: 123456