The most likely cause of a computer slowing down gradually is adware/spyware infection. Adware and spyware are malicious programs that can be installed on your computer without your knowledge or consent. They can slow down your computer by running in the background and using up resources, such as CPU and memory. They can also track your online activity and collect personal information about you.
Overheating can also cause a computer to slow down, but it is less likely to be the cause of a gradual slowdown. Overheating usually occurs when the computer’s cooling system is not working properly. This can happen if the computer is dusty or if the fan is not working.
A processor chip that is getting old is not likely to cause a computer to slow down gradually. However, if the processor chip is damaged, it can cause the computer to crash or freeze.
Dropping a sandwich in your computer is very likely to cause the computer to stop working. The sandwich will likely get into the computer’s components and cause damage.
Therefore, the most likely cause of a computer slowing down gradually is adware/spyware infection.