Peachtree's check forms are saved with a default standard letter paper size (8.5" x 11"). In order to print 6.5" checks, you must customize the paper size for your form. Additionally, in order to print 6.5" check forms you may need to install a dot matrix printer driver through Windows.
Select Start from the Windows status bar then select Printers and Faxes.
On the Printers and Faxes window, choose File from the main menu, and then select Server Properties.
On the Server Properties window, place a check mark in the Create a new form box.
Enter the Form name and define the Paper size in the Form description (measurements) area.
Click OK to save the form.
Now that you have installed the printer driver necessary to print your 6.5" checks, you must customize your check forms to print a 6.5" length.
For Peachtree 2008, 2009, 2010:
From the main Peachtree menu, select Reports & Forms, Forms, and Checks or Payroll Checks, depending on the type of check you want to print.
On the left pane, click once to select the check form that you wish to use. One-stub forms are generally used for 6.5" checks.
Once the desired form is highlighted, click Customize to open the Form Design window.
At the top of the window, click Print, and then Setup.
On the Page Setup window, on the Paper Size selection, select the custom 6.5" paper size that you had set up earlier. Click OK.
Click the Save button and enter a new name for this check form. It is advisable to enter a description as well. Both the name and description should indicate that this is your customized check for printing 6.5" continuous checks, such as 6.5" Custom AP Check.
Click OK to complete this setup.
Note: Your actual steps may vary depending on your operating system and printer driver. Regardless of your operating system you should probably specify that the paper source is Automatically Select.