How to activate location services on my Iphone 4?

Since upgrading to iOS7 the location services I can't switch on as it won't let me slide it across and I Don't no mtge restrictions pass code as phone was 2nd hand so I can't back it up to iCloud after either as resrictions pass code will still be on there Help!

You can turn Location Services on or off at Settings > Location Services. Location Services is on by default, but you can turn it off if you don't want to use this feature or to conserve battery life. You can individually control which apps have access to Location Services data. If you turn Location Services off, you'll be prompted to turn it on again the next time an application tries to use this feature.
Resetting location warnings

Location warnings are the requests made by apps (such as Camera, Compass, Maps and location-dependent third-party apps) to use Location Services with those applications. An app will present a location warning the first time it needs to access Location Services data. Tapping OK gives that app permission to use Location Services as needed. Tapping Don't Allow prevents an app from accessing Location Services data from then on.
If you want to change whether an app can or can't access Location Services data, you can either change the individual setting for that app at Settings > Location Services, or you can force all apps to prompt you with the location warning again using Settings > General > Reset > Reset Location Warnings.
Improving GPS Accuracy (iPhone and iPad Wi-Fi + 3G Only)2

GPS accuracy varies depending on the number of visible GPS satellites. Locating all visible satellites can take several minutes, with accuracy gradually increasing over time. Use these tips to improve GPS accuracy:

Ensure the date, time, and time zone are correctly set on the device in Settings > General > Date & Time. If possible, use Set Automatically. Important: Incorrect settings on your computer can sync to your device. Verify the date, time, and time zone on any computer that syncs with your device.
Verify that you have a cellular or Wi-Fi network connection. This allows the Assisted GPS (A-GPS) on the device to locate visible GPS satellites faster, in addition to providing initial location information using the Wi-Fi or cellular networks. Note: Microcells (sometimes called Femtocells) are not supported with Location Services.
Maintain a clear view of the horizon in several directions. Keep in mind that walls, vehicle roofs, tall buildings, mountains, and other obstructions can block line of sight to GPS satellites. When this occurs, your device will automatically use Wi-Fi or cellular networks to determine your position, until the GPS satellites are visible again.