I bought our son a Spynet Video watch for Christmas and we charged it but when we removed it from the charger, it turned off and wouldn't turn on. I then thought maybe we needed to download some kind of software first but when I went to the spynethq.com website, I couldn't find a link to download the spynet client application

A bit late to the party, but two things come to mind. If the watch is new old stock with a few years on it, more than likely the battery is bad, it won't charge any more. Also, the power supply may be bad, I use 5 volt one amp charger, also, the manual says to charge it with the screen on, I tried that, and the battery will never be fully charged because the screen being on drains the battery faster than the charger can charge it.If the watch is working but the battery is low, connect the charge cable to the watch, then to the charger, otherwise the charger will pull the battery down too. So, let the screen go blank, then charge it, I have tried this method multiple times, and every time, assuming the battery is good, it fully charges in few hours. If you are adventurous, you can upgrade the battery to 450mah, it's a little bigger than the one it comes with, but lasts a lot longer, only a small amount of modification to the plastic strips made into the watch back need to be done, simply remove the strip closest to the electronics and it will fit just fine.