Should I buy new laptop in Japan?

i know that this question has been asked, like thousand times, but, i'll ask it anyway.i'm planning to go studying in japan soon. and here my laptop is, like seriously outdated, and this is a good opportunity to buy new laptop.
here's the question :
1. should i buy it at my country (indonesia) or japan?
i've done some research, and i see that the keyboard, os, and etc is in japanese if i buy at japan. you could say that's good for me who will studying Japanese. but some say the prices for laptop is high in japan. while here in indonesia laptop is cheap. and its kind of reassuring for me, who will go to foreign country first time to have laptop in at least language that i understand.

2. if i buy the laptop here (indonesia), if by any chance my laptop is busted while i'm at japan, will i easily find service center, will the guarantee credit/contract still legit to use there?

If you will be studying in Japan then consider getting a Japanese laptop while you are here. I wouldn't worry too much about relative prices if you are not in the market for something specific. There is a huge variety so you'll probably be able to find something in your price range.

2. if i buy the laptop here (indonesia), if by any chance my laptop is busted while i'm at japan, will i easily find service center, will the guarantee credit/contract still legit to use there?

Only if you have an international warranty. Otherwise you will probably need to send it back to Indonesia for repair.

will the difference in os and keyboard be some kind of burden for me while in japan?
and there are shop who sells japanese keyboard right, will my laptop work if i use that?
since there are difference in os

It's not a big burden unless you are trying to troubleshoot a problem. But you can easily change the system language on most recent OSs which helps in these situations.

hmmm, isee.. i'll buy it here then. thank you very much for the info ^^