I have a computer but I don't use it often (about once a month). Every time I turn on the computer, it slows down noticeably and the fan just gets louder and louder. It still slows down overtime even after I made sure there is no dust inside the computer. I wondered why, and how can I stop it?
PS. I use Windows 8. HP TouchSmart 300. CPU: AMD Athlon II X2 235e. 4GB RAM. 500GB HDD.
I can only guess. Is it Windows? If the computer was turned off for a long time, it could be possible that Microsoft Windows Update and other Update programs (Antivirus programs, Quicktime, Java, Flash, etc.) are running in the background. Such Microsoft Updates and patches are published every month and can slow down the computer. The CPU can be active then a lot, too. If you are using Windows (what I guess now), are you able to see what process or which processes are using the CPU in the main at that time (see Windows Task Manager)? As kobaltz said, more specifications of the computer and the used operating system might be very helpful.