A computer crash occurs when a computer stops functioning properly, often resulting in the loss of unsaved work. This can happen due to various reasons, such as software bugs, hardware failures, or overheating. When a crash happens, the screen may freeze, or an error message may appear, requiring a restart to regain functionality. To prevent crashes, users can regularly update their operating system and software, maintain adequate cooling, and ensure that hardware components are in good condition. Additionally, using reliable antivirus software can help protect against malware that may cause crashes. Regular backups of important files are also recommended to avoid data loss.