Using a new checking account than previously - wrote checks but now system says no check to print ??

Thanks for posting in the Community, @paige4.

It's possible that the Print Later box is not checked that's why they're not showing. Let's open those checks in the Register to verify.

Here's how:

1. In QuickBooks Online (QBO), go to the Accounting menu at the left pane to get to the Chart of Accounts.
2. Locate the new checking account that you're using, then tick View register under the Action column. 
3. Select the check, then click the Edit option to open the transaction. 
4. Place a checkmark on the Print later box. 
5. Hit Save and close and do the same steps for the other checks.

Once done, you can now proceed on printing them. Check out this article for further guidance on how to do it: Print checks.

I also recommend visiting these articles if you'll encounter any printing problems:

• Fix QuickBooks Online printing issues on browsers for Windows
• Resolve PDF printing issues
• Test sequence for PDF printing issues

Please know that I'm only a post away if you have any other questions or concerns. I'll be more than happy to help. Have a wonderful day!