Hi there! I'm sorry to hear that you're experiencing this issue in Excel 2007. This can be frustrating, but I'll do my best to help you out.

First, it's important to note that Microsoft does not officially recognize this as a problem. However, it's possible that it could be caused by a glitch or bug in the software.

Here are a few additional steps you can try to resolve the issue:

1. Check your keyboard: Sometimes, this issue can be caused by a stuck key on your keyboard. Make sure that none of your keys are stuck or pressed down.
   
2. Check your mouse: If you're using a mouse with a scroll wheel, try clicking the scroll wheel to see if that resolves the issue. You can also try using a different mouse to see if that makes a difference.
   
3. Check your settings: Go to the Excel Options menu (click the Office button in the top left corner of the screen, then click Excel Options) and click on the Advanced tab. Look for the "Allow editing directly in cells" option and make sure it is checked. If it's not checked, try checking it and see if that resolves the issue.
   
4. Try repairing or reinstalling Excel: If none of the above steps work, it's possible that there is a problem with your Excel installation. Try repairing or reinstalling Excel to see if that resolves the issue.

I hope these steps help you resolve the issue! Let me know if you have any other questions or concerns.