You didn't have GW510A (limited edition) Assume this is similar?

CTL1616 and there is a video on you tube showing you how to do it.

I assume this is the casio Forester.

hi,
Press and hold 4 buttons on the four corners at the same time for 3 seconds to reset the watch after battrey replacement. check the last page of the manual for the same.

http://www.nike.com/timing/extranet/product/os_alticomp/osac_manual_eng.pdf

If it doesn't help then try another new battrey.
OK

The CTL 1616 is a special device.
It's not really a battery, but a "capacitor", which means, that it's mainly supplied by the energy of the light. The capacitor is designed to maintain the functions only for (short) periods of darkness.
It's NOT a "standard lithium battery", because It has a different voltage (2.3 V instead of 3 V) and consists of different materials.
Unfortunately, the capacitor loses its ability to store the energy over the time. So your watch may be able to maintain all the functions for more than 11 months of darkness in the BEGINNING, but after a few years it may only last for a few hours!
However this may be STRONGLY influenced by the use of the functions: for example the automatic reception of radio signals or using a digital compass may strain the energy seriously.
So, the use of different functions may affect the lifetime of a CTL 1616.
I also recommend to expose the watch to (bright) light as often as possible in order to maintain a HIGH level of stored energy.
I also heared that there were serious problems with the quality of this type of capacitor a few years ago. Maybe a new CTL 1616 will last for decades.

You likely have a dead battery. Follow the instructions on this web site http://forums.watchuseek.com/f43/how-change-ctl1616-rechargeable-battery-41076.html
it is clear and covers most casio models. Watch closely for the springs when taking your watch apart. You can order the battery online (the best option) but most people that use a standard lithium battery seem to have no problem.

mcdevito75 Here, hopefully you didn"t buy the batteries all from the same store, as watch batteries and all batteries have a shelf life of not too long. You may have bought weak batteries if all were bought from the same store, nothing to do about that as who knows the strength of packaged batteries. If you did buy all the batteries from one store, try another store and buy another battery, If the watch still stops and goes, your watch may be wearing out, specially if the watch is over 10 years old.

mcdevito75 here, Possibly the battery is worn out. An old battery will not hold a charge, Visit a small watch repair shop in yourarea for a new battery.

Ebay: http://shop.ebay.com/idiotdoc/m.html?_nkw=Casio+G-Shock+CTL1616+CTL+1616+Panasonic+Watch+Battery]&_sacat=0&_odkw=&_osacat=0&bkBtn=&_trksid=p3911.m270.l1313

If you left your watch in direct sunlight, there should be just 6-8 hours enough to recharge it. If there was no direct sunlight, it may take up to a week to revoke your watch. This corresponds only to watches powered by light. The energy cell in those watches is called capacitor, not battery. If you are not sure what type of cell your watch has, leave it for a few days more in bright lightened place and then see if it works. If it does not - replace the capacitor (or battery if your watch isn't powered by light). Rate me, plz.

CTL is the designation for a rechargeable secondary battery. The CR is a primary disposable battery and is a 3 volt cell. The CTL1616 while the same size as the CR1616 function completely differently and are not interchangeable. The CTL1616 is 2.3 volts and is recharged by solar or light or kinetic movement. The CR1616 is 3 volts is not rechargeable and will not function properly in a time piece designed for a 2.3 volt circuit. There is only one manufacturer of the CTL1616, Panasonic and they sell through Casio parts distribution.

Hey all, here is a site that has good instructions on how to change the battery in your G-Shock watch. Sounds like you are suffering a low batt problem.

http://forums.watchuseek.com/showthread.php?t=20217

If you want to ensure you still have a the same water resistance rating, I do suggest that you take it to a watch guy to have it replaced for you. They clean switch contacts also and you keep water resistance rating. Good Luck and vote this as a "FixYa". Cheers

regards
Graeme