hi my iphone 3g wont charge or connect to my computer when turned on. but when the iphone is turnes off it will charge. it has been doing this...

Thank you for your question. I'll do my best to assist you.

Many iPhone and iPad users are having trouble with their devices after updating to iOS 5 which sometimes happen that software is mainly configured for the new device they released (iPhone 4S). Unfortunately, Apple does not support reverting back to the old software so that will not be an option. You can probably try restoring you phone to its factory default where you will need to delete all the data saved in your iPhone. If that will not fix the issue, you will have to wait for the next software update.

One of the reasons why its not showing "charging" on your screen while your iPhone is On and connected to computer is probably because the new software disabled the charging status when it recognizes a power less than it requires (10 Watts). Even if its not saying "Charging", it is still charging but it will just take longer than normal. And when your iPhone is OFF, its not using the power that your computer delivers to charge your iPhone that is why its saying Charging.

Watch this video that I found for you. It doesn't explain exactly about you concern but I hope that it will help to understand more about it.

I hope this answers your question. If it does, please click the Accept Answer button below the answer. You must be logged in to see this button. If you have any follow-up questions, please post your comments below this answer.

Thanks again.
Glenn