If anybody has read this, thank you for your time. As a final resort, I quite literally pulled every single wire out of the computer--EVERYTHING, from the CD drive to the power supply to the graphics card to the memory. Every single connection was disconnected and cleaned accordingly. Upon reassembly, the issue did not return. All I can assume is that the issue lay somewhere within the device.
For approximately the last two weeks, my computer has been suffering from perpetual and uncontrollable downward scrolling every time that my cursor hovers over a drop-down list or scrollable list. This includes the Windows Start menu and Control Panel dialog boxes, website drop-downs, in-game drop-downs, etc. For some reason this does NOT affect pages--website pages, Word pages, or this very text box in which I write now.
It is also impossible to click-and-drag in all settings except to highlight text within a page.
Here's what I have tried:
Full reboot. Nothing. No change.
General device troubleshooting. Inconclusive. It is NOT my wired mouse nor my wired keyboard, as I have swapped both out for a relative's units. It is NOT my sketch pen input--problem persists even when no mouse is connected or when the pen is not connected. It is--to the best I can tell--NOT the USB ports, as the problem persists no matter which of my 13 USB ports is receiving input.
Malware scan. McAfee has given me a shiny bill of health.
System restore. I reset the system to the oldest restore available to me, just before a Windows "critical update." I was greeted with a message afterward saying that the system restore had failed for unknown reasons, and that nothing had been altered. This occurred twice.
Manually uninstalling recent software and system updates. I have uninstalled/repaired EVERY update that took place on this computer since the beginning of December. Nothing has fixed this issue.
It's been frustrating, since I have researched many other online help forums (a few right here on CNET) and people have had similar issues resolved with compressed air, replaced batteries, software uninstallation--all ineffective for my device. Also, with the way that my university's online class system is designed, it will be next to impossible to use this computer for classes. If not for that, I might suck it up and deal with it.
I am not in a position to buy a new computer at this time, so any and all feedback would be greatly appreciated.
Lenovo Intel i5 PC - 4 years old and otherwise healthy
Windows 10 Home
Issue began: early December.