When you got a problem with your computer, you should know the the market where you bought the PC or Laptop usually gives you a warranty, where you can go back with your Computer and no matter what the problem will be they will fix it, but before, you should know following things.
How warranty works ?
Usually a computer warranty is available for one year, after one you can still repair your computer by paying the cost of repairs. During the warranty the service will repair only the things that will be proved to be broken because of factory defect. If you dropped your computer, or poor some water on it, the service will not repair your computer on warrant and you will have to pay all the costs if you want your computer to be fixed.
Where to repair your computer ?
You can go exact to the same shop you bought the computer to ask for help, or they can give you an address of service center where you can go and repair your computer if you have any problems. Also you have to check if in your country is an official Service Center from manufacturer, you can ask help right from them, this is the best solution to ask help from.
Before asking help
Before asking any help check for the problem, if there is a software problem there always can be a guy who can try to fix it, maybe it needs just a reinstall. If there is a hardware problem you should not ask anyone to help to fix it, especially when your computer is still on warranty, if someone will try to check you hardware the warranty will be void, and the Service Center will not fix you the computer for free.
If you have some more questions, write them in comments.