For more information regarding common troubleshooting issues check out Commodore 64 Troubleshooting.
Background and Identification
The Commodore 64 sold over 14 million units world wide and to this day is the most successful selling computer ever made. The Commodore 64C version was basically identical to the original however packaged in a more streamlined case with an improved sound chip.
Part of the success of the Commodore 64 was that it was sold in retail stores instead of just electronic stores. The system has 64 Kilobytes of RAM and hence the name Commodore 64.
In today's standards this computer seems hopelessly out of date and pretty useless. That all depends on what you are comparing it with and what you want it to do. For it's time it was a very powerful machine and light years ahead of it's competition in more than just it's price tag.
The Commodore 64C is a true computer but is also a very good machine for playing games. Many thousands of game titles and upwards of 10,000 commercial software products were released for the Commodore 64.
The system required the use of basic commands in order to operate using the Basic computer language. The Commodore 64C did however come with the GEOS operating system should you prefer to do things more traditionally.