The charging system is not working new battery keeps going dead. How do I troubleshoot to find the real problem?

With a meter, the battery should have 12 volts at rest. With the engine running and no accessories on, the charging system should be producing 13.5 - 14.5 volts.
You could have a battery problem, a charging problem, or something draining the battery when the engine is off.

Sounds like the battery is no good (not holding a charge)

Check you charging system, with a volt meter is should show between 13.5-14-5vdc at the battery with the engine at 2000 RPM. Test your battery for load capacity and dead or weak cells...1 dead cell will drain the others. Hope this helps.

Put a charger on the battery for two or three hours. Now start the bike up and use a voltmeter to measure the voltage across the two battery terminals while the engine is running around 2000 rpm. The meter should read around 14 volts. If not, the charging system needs to be checked. If the charging system is working properly then yes, something is draining the battery. You will need to check all the wiring and switches to locate the source.

The cap on the positive battery cable can be pulling out and it has a thearther to not lose it. Some on them have two battery cables and their well known to get corrosion under the bolts and bewteen the cables and the side of the battery the bolt head is 5/16 or 8 MM and needs to be taken apart and all cleaned and connected it's best to charge a low battery or change it as the altenator can go up in smoke after a few minutes charging a dead or low battery after a jump start. If nessary connect the jumper car with it running and let it sit there charging for awhile, then start the dead car and still leave it connected to stableize the charge and not ruin either car. Once running take the car to a parts store or service center and have them test the battery and the charging system. You can aquire a battery charger if you can get an extion cord to the car and charge the battery and in a few hours the car will start if the battery is any good and the charger works correctly. If the battery is real cold and real dead it's possible the battery can explode if jumped off wrong or making a spark. Be real careful with low and dead batteries as they can spray acid in your eyes and on your skin and sparping lots of water on yourself in the cold is a bad deal. and lots of water is the only good way to deal with the acid.

no operating system even stated.
Xp/vista/w7/w9/w10/ linux ,what.... must we guess?

is your internet connection working? it must or PNP will be near brain DEAD ,do that first.
ok guess w10.
why not see if OTHER USB works first
barrow a real mouse not that battery dead wireless wonder mouse?
get a real mouse
make sure that works
then put in a new battery in your wireless mouse
RTM it tells you how
USB tests, all so obvious.
use real desktop key board , that work
or USB memory stick , add file to it, see other files you have there>?

only clues here is USB dead, 2 months old.(means new? or new to you?)

next,
in w10
go to CP
then go to device manager
be ONLINE
see yell or red error there that driver stack?
bingo bad driver
reload any that are bad.

end story
google how to reload a windows 10 driver, be like 10,000,0000 hits.

Have you checked to see if the alternator is charging ? Run a volt meter on the battery with the engine running, have to have more than 14 volts. If 13 or less, then replace the alt.

I had this exact same problem on a hipster 125, it was a faulty regulator module ( mounted under the seat) I also found a short circuit (somewhere) in the wiring loom between the regulator output and the chassis (probably what killed the regulator in the first place!) I cut and replaced the entire wire to save removing most of the loom and after testing reg to ensure it was dead i fitted a new one (about £60) bike charges and runs like a dream now even with fully lights approx 80% of the time. good luck

you could have a fault on your regulator/rectifier a chech with a multi meter will tell you. also check generator output.

The only solution is to get a new battery. When you do, charge it completely when you first get it, then discharge it until it dies. This will maximize the life of the battery.