When I try to sync devices (iPad, iPhone) iTunes doesn't recognize the device

You have the latest version of iTunes installed on your computer ?

There is some troubleshooting on these pages for when a device doesn't show in iTunes :

PC : http://support.apple.com/kb/TS1538

Mac : pchttp://support.apple.com/kb/TS1591

i have tried all the ideas here PC : http://support.apple.com/kb/TS1538 and i still can not sync my iphone 5c, iphone 3gs or my iphone 5s

If the phones don't show up in iTunes when connected, have they ever shown iTunes on that computer ? You've tried completely uninstalling iTunes and reinstalling it, and you don't have any third-party software that might be conflicting with iTunes (bottom of that page) ?

thank you for your reply! This is my only computer (pc laptop) and has been for a few years. i have synced to this computer multiple times. i have tried completely uninstalling itunes down to removing bonjour and i checked for third party software and its not blocking it. i cant even acess the pictures on my computer from the phone when hooked through usb. i have checked the cables and used three different ones. thank you again!

Do you get any sound from the phones when you connect them to the computer, and/or any indication on them that they've connected to it e.g. do their screens come on when you connect them ?

It's been a while since I used iTunes on Windows, you might be better off starting a new thread in the iTunes For Windows forum on here : iTunes for Windows

and say that you've already gone through the troubleshooting on that page, and that it used to work on that computer (nothing has changed since you last successfully synced e.g. you haven't updated or reinstalled on the OS on the computer, and other devices are recognised by the computer's USB ports e.g external drives ?)

yes i get the tone i usually get when plugging in a usb device. it also charges the devices and asks to trust the computer. thanks for your help so far!