You NEED a GOOD surge suppressor. Go to a computer shop or office supply store and look for one that guarantees forever to replace your computer if a power surge occurs from that surge suppressor. Your computer has a storage area for files and information. This is called the hard disk. During each use programs are pulled into memory, files may be created, deleted, changed.
Filing becomes irregular, parts of files being stored in different places.
This makes it slower and more difficult for the computer to find things, so it is a good practice every few days to do something called Defragmentation. This process brings files back into line, in neat little rows. Usually, now and then the computer will make an error on the hard disk. So, once in awhile when doing a defrag, the computer will tell you to run scandisk before doing anything else. I do one once a week or even more.