Where i can learn hardware maintenance?
What type of maintenance you want to learn...! If it is windows or linux then i can help...!
If you dont have access to a community college, university or other technical school that offers computer repair classes... I'd recommend that you take a look at this book. I think its the most comprehensive with regards to computer repair/maintenance. I used these books in all of the courses I tought related to computer maintenance.
Then, part 2 is to practice. Without hands on work, its going to be difficult to learn about computer hardware maintenance. This is one of those things in life like learning how to ride a bicycle...you can read about it but you have to actually practice to master it.