There's a simple truth buried in this question: the problem isn't the spreadsheet, it's the tool. When one user on a shared sheet experiences erratic cell selection, clicking A25 and watching A3 through A25 light up, while everyone else works without issue, the natural instinct is to blame the hardware. The user swapped mice, changed mouse pads, and the issue persisted. That's not a hardware problem. That's a symptom of a tool that treats the input layer as an afterthought.
Traditional spreadsheets were designed for a world where a single person clicked a single cell on a single machine. They weren't built for shared environments, touchpads with variable sensitivity, or the subtle drift of a multi-user workflow. The fact that this behavior appears on only one computer in a shared sheet tells us exactly where the friction lives: in the brittle connection between how a user intends to click and how the application interprets that click. Excel's selection engine is rigid. It assumes precision. It has no room for the messy reality of human interaction.
What this means for you is straightforward: you're spending time debugging a workaround for a limitation that shouldn't exist. You've eliminated the obvious causes, mouse, surface, driver, and you're left with a ghost in the machine. That ghost is the spreadsheet's inability to distinguish between a deliberate selection and an accidental drag. An AI-native spreadsheet would see the pattern. It would recognize that you click A25 with the same cadence every time, and it would learn to reject the spurious range that appears only when your hand trembles or the pad misreads. It wouldn't wait for you to diagnose the issue; it would adapt to your input.
The fix for this specific problem might be a registry tweak, a driver rollback, or a hidden setting buried in Excel's options. That's the wrong answer. The right answer is a tool that understands intent, not just coordinates. If your spreadsheet can't tell the difference between a click and a drag, you're not using a spreadsheet, you're fighting one. Stop troubleshooting the symptom and start asking why your data tool doesn't work the way you do.