Assuming that your phone is not working as intended, then you're probably weighing the pros and cons of master resetting your device. Applying a factory reset results in loss of personal data, in case there are no backups in place. As such, it's advised that, before you master reset your smartphone, you try to fix its issues by wiping the cache partition and removing malicious apps through safe mode. Here's what you need to know:

Wiping the Cache Partition:

1. Make sure your phone isn't plugged to a charger or USB cable
2. Disable "Fast boot". To do so, swipe the status bar down using two fingers, tap "Settings" > "Power" and clear the check box associated with "Fast boot"
3. Turn off your smartphone
4. Press and hold the "Volume Down" key
5. Press and release the "Power" button to turn on the device, but continue holding the "Volume Down" button
6. Release the "Volume Down" button after the three Androids appear at the bottom side of the screen
7. You should now see a list of options, including "Fastboot", "Recovery", "Factory reset" etc. NOTE: if you can only see "HBOOT" and "FASTBOOT", this means that you've pressed the "Back" button. If so, press "Back" again or press "Power" with "HBOOT" highlighted
8. Navigate to and highlight "Recovery", using the "Volume Down" button
9. Press the "Power" key
10. A red triangle should appear on the screen. At this point, hold the "Volume Up" button and press "Power" simultaneously
11. You should now see a menu with blue text, giving you a list of options
12. Use the "Volume Down" button to highlight "Wipe cache partition"
13. Press the "Power" key to select the option. The process will commence
14. After a while, you should see the "Cache wipe complete" message on-screen
15. Press the "Power" button and select "Reboot system now"

NOTE: If wiping the cache hasn't helped fixing the issues on your device, then you might have to factory reset it. Please visit this link for a full guide on master resetting the Desire 700.

Safe Mode

Safe mode is a great tool that allows you to reboot your smartphone with all the third party applications disabled. This is useful assuming that you have installed a malicious third party app that is preventing you from uninstalling it in normal mode.

Enabling Safe Mode:

1. From the home screen, press and hold the "Power" button
2. Tap and hold the "Power off" option
3. You will see a pop-up message informing you that you're about to enter "Safe mode". Tap "Restart"
4. Once the device reboots, you should see a "Safe mode" label at the lower-left area of the screen

Uninstalling a Third Party App:

1. In safe mode, tap the "Applications" icon located on the home screen
2. Tap "Settings" > "Application manager"
3. Swipe to the "Downloaded" screen
4. Select application that you wish to remove and tap "Uninstall"
5. Press "OK" to confirm

To exit safe mode:

1. Press and hold the "Power" button
2. Tap "Restart"
3. Tap "Restart" a second time and your smartphone should reboot in normal mode. (The "Safe Mode" label should not be present).