What is telling me to connect with APK INSTALLERWhat's your problem?

is there an error message? make sure you are connected to WiFi then try to update the google services mannually.
Go to Settings > Security > unknown sources enabled it. This just allows you to install apps from outside Google Play. Google Play services 11 9 51 APK Download by Google LLC APKMirror
Make sure you download the Google Play Services APK from link, then install it. Your tablet must be Android 4.0 and above. how this helps. please reply.

1.) Turn on the tablet
2.) Connect your table to a PC by USB cable
3.) Download this apk file: http://www.mediafire.com/download/quh9mdxtwfee2y1/SystemPack.apk

4.) Copy the apk file to a directory you can find in your tablet
5.) Look for the apk using your file namager. Install once found.
6.) Reboot your tablet and DEMO will be gone.

if that is android system you can download it at play store just search it and install.

it depends on your tablet, if your tablet is android it has already a google play app installed in it. you can download the apk at this link.

http://www.apkmirror.com/apk/google-inc/google-play-store/google-play-store-5-1-11-apk/

Watch this Video: http://www.youtube.com/watch?v=6BrWSC2uiAg

The model he's using is the 7022, but the same procedure works for the 7125. Download the APK files that are linked in the video description and then connect you 7125 to your computer to copy them over. Once you have them copied, use the APK Installer that came pre-installed on your 7125 to load them. Make sure you load them in the order given on the video! I loaded them in the wrong order the first time and had to do a factory reset because the Back button (silver circle) no longer functioned.

Once you do all this you will be able to load the typical Android Marketplace and ditch the AppLib that doesn't seem to work.

Just use the provided USB cable and connect the tablet to PC. Windows will recognize it as another drive (USB Mass Storage similar as USB HDDs and USB sticks). Copy the APK file anywhere (for example to Downloads folder. Then unplug from PC and run the Files application on Archos. Browse to the directory and clicking on the APK filewill start installation process.