Installl new keyboard and mouse.

1. Plug the new keyboard and mouse directly into the PC first. If they are USB devices, avoid a USB hub if possible.
2. Wait a short time after connecting them so Windows can load the device driver.
3. If they do not respond, unplug them, wait a little while, and plug them back in.
4. Try a different USB port on the PC.
5. If the new devices are wireless:
   • Make sure the batteries are fresh or fully charged.
   • If they use a USB receiver, unplug the receiver, wait about 10 seconds, then plug it back in.
   • Check for a Reset button on the device or USB receiver and use it if present.
6. If the new keyboard or mouse still does not work, connect them to another PC to confirm the devices work there.
7. If Windows detects the new devices but scrolling or pointer behavior is not correct, open mouse settings:
   • Windows 10: Start > Settings > Devices > Mouse
   • Adjust scroll behavior, pointer speed, and button settings there.
8. If the new devices are still not working correctly, check for driver updates:
   • In the taskbar search box, type check for updates and select Check for updates.
   • Under Windows Update, select Check for updates.
   • If needed, open Device Manager, find the device, open its Driver tab, and select Update Driver.

If the old mouse is causing unwanted scrolling, replacing it with a wired USB mouse temporarily is the simplest way to regain control while setting up the new devices.

References:

• Mouse and keyboard problems in Windows
• Troubleshoot problems with your Surface mouse or keyboard
• Use Microsoft Ergonomic Mouse
• Set up Surface Mobile Mouse