Excel centers text when I press Enter

Excel 2010
Windows 10

I recently installed Office 2010 on my new Acer laptop. In Excel, when I enter text in a cell that includes a number, even if includes alphabetic text, then press Enter or an Arrow key to complete cell entry and move on, Excel centers the text in the cell, even if the cell is not formatted that way (that is, left/center/right justification are all null). If I enter only text, pressing Enter or an Arrow key leaves the cell contents left-justified (the default). This does NOT happen on my Dell laptop running the same version of Windows and Microsoft office. Even after I export the UI customizations on the older Dell, and import them on the Acer, I get the same behavior. And I visually compared the Excel settings on both the Dell and the Acer, and they seem to be all the same.
Can anyone explain why Excel on the Acer centers the text?
TIA,
Jeff

Nope. It's just a plain ol' cell.