All of a sudden my payroll summary report doesn't open on my desktop computer, but it loads on my laptop. What could the issue be?

I'd be glad to sort things out for you, @jen-cowell.

Possible reason that you're experiencing this, is due to some browsing related issues on your computer. We can perform some steps to fix this. It could be that the cache stored in your browser is causing the issue. Let's start by accessing your account through an incognito browser. You can use these keyboard shortcuts:

• Google Chrome: press Ctrl + Shift + N
• Mozilla Firefox: press Ctrl + Shift + N
• Safari: press Command + Shift + N

Once signed in, let's try to open your payroll summary report on your computer, If it works, let's go back to your regular browser and clear the cache to refresh the system. If not, I recommend using other supported browsers.I've also added these articles that can guide you with the task in accessing reports in QuickBooks Online: 

• Customize reports
• Memorize reports

Feel at ease to get back in here if you need clarifications in accessing reports in QBO. I'm always here to help you. Have a blessed day.