Hello,
Are you using a wireless connection, a Bluetooth connection, or a wired connection? Please let me know how your mouse is connected first so we can troubleshoot in the right direction. Thank you.
You mentioned that your computer is searching for the mouse, so I’m guessing you are using Bluetooth. Please open Device Manager, find your Bluetooth and mouse devices, choose Uninstall, and make sure to check the option to delete the driver software. Then restart your computer — this will automatically reinstall both drivers.
After restarting, press and hold the pairing button on your mouse for a few seconds until the light starts flashing to enter pairing mode. Then check again in Windows to see if the mouse appears and can be connected.