Hey Jane,
There are many reasons why we have a flashing red light on a Microsoft wireless mouse. The mouse's software may need an update, you're battery may need to be replaced or recharged, you're wireless device may be connected to a non working port, something may be interfering with the wireless mouse.
Here are few tips you may follow and see if that helps.
- Download and install the latest mouse drivers based on the computer system type from http://www.microsoft.com/hardware/en-us/p/wireless-mobile-mouse-3500#support
2. Sometimes, one wireless device can interfere with another. Look at the bottom of your mouse to see if it has a button to sync it to the receiver. If so, press this button. Doing so will resync the mouse using a different channel. Turn the receiver upside down or on its side to see if you are able to get a better connection. Remove other nearby wireless devices, such as a cordless or cellular telephone and make sure the mouse is at least eight inches away from a wireless keyboard. Make sure the mouse is not on a metallic surface or very close to metallic objects.
- Try using a Mouse pad instead of using it on a glassy or a metallic surfaces.
- Make sure the batteries are inserted properly. Open the battery compartment. Check for and remove anything that could be obstructing the batteries connection. Look for corrosion as well and remove it, if possible.
Hope this helps.