Hi,
my ipad 1st generation doesn't charge anymore.
I tried two different cable, in the wall and in the computer.
The only thing happen when I try to start the ipad is the need to charge screen, the cable with a little lightnight bolt.
Hello and welcome to the forum!

As already stated, you should simply upgrade to a more recent iPad model rather than trying to revive an antique - Apple charges $99 (+ S/H) to replace the battery - that money would be better invested in a newer model.
Now, you can evaluate battery health in several ways - the two that I've used on my nearly year and a half old iPad Air 2 is
Battery Health (available in the iPad App Store) &
Coconut Battery, an app on my laptop which can check the iPad's battery health once the device is plugged into a USB port - below are screen captures from both of these assessments - my iPad's battery is rated as having 84% health (i.e. present charging capacity compared to its condition when new) and 232 cycles - batteries for these iDevices will typically reached about 80% nearing 500 cycles - I suspect that if you test your iPad 1 battery, these numbers will be poor.
Finally, there are plenty of DIY iPad guides at
iFixit, including battery replacements in these devices - cost might be half for the new battery and other equipment needed to do the 'teardown', BUT these are difficult procedures and time consuming, probably not something I would do. Good luck and let us know the condition of that battery if you obtain one of the apps above - Dave
.