Vikki Eady, you did not tell us which model Moto G you have. So here are instructions for the 1st gen. This will depend on your version of Android:"
If you are unable to access the phone's menu to perform the standard reset you can attempt an external factory reset.
When using this feature; everything is deleted from the device.
Reset will require a minimum battery level of 25%. If you are unable to perform a reset, please charge for 20-30 minutes and try reset again.
1. Ensure the device is powered off, and unplugged
2. Press and hold the Volume Down button and Power button (located on the right edge of the device) for approximately 3 seconds then release.
3. From the "Boot Mode Selection Menu" screen, select Recovery.
Note: Use the Volume Down button to scroll through the menu options and the Volume Up button to select.
4. From the "No Command" screen (Android figure lying on his back), press and hold the Power button then press and release the Volume Up button to display the menu options.
5. Select "wipe data/factory reset".
Note: Use the Volume buttons to highlight and the Power button to select.
6. Select Yes -- delete all user data.
Note: Allow several seconds for the factory data reset process to complete.
7. Select reboot system now.
Note: Allow several minutes for the reboot process to complete.
1. With the phone powered off, press the VOL DOWN KEY for 2-3 seconds then POWER key then release.
2. The device will display different BOOT OPTIONS
3. Use the VOL DOWN Key to SCROLL to Recovery and VOL UP Key to select
Tip: If the device reboots, you may have waited to long to make a selection, you will need to begin the process again.
4. The device will display the Motorola logo and then the Android in distress ( logo with Exclamation mark)
5. Press and hold the VOL UP key for 10-15 seconds. While still holding the VOL UP key tap and release the POWER key
Tip: You can try this step, holding the phone in landscape. If you are stuck on step 6, try a force reboot by pressing the Power key and Vol Down key, and start the process again.
6. The device will display additional menu options (Text will appear in BLUE)
7. Use the VOL DOWN Key to scroll to Wipe data / factory reset and the POWER Key to select this option
8. Use the VOL DOWN key again to select YES - delete all user data and press the POWER key to CONFIRM
9. Once the Formatting is complete, press the POWER key to confirm a REBOOT
10. The device will reboot and start the normal power up sequence