To make sure it looks how you want it to look, or to make sure all the info is correct and we're it should be.
Press on an application, and press Ctrl and D together on a keyboard which means delete or unistall.
Is the answer supposed to be more specific?
Answer:
All of the files are stored on a hard-drive. Except for the files you just viewed before turning off the computer, which is stored in the RAM (Random Access Memory). If your computer is a desktop, and the power goes out while looking at a photo/pdf, you may corrupt/lose the image if the computer didn't have enough time to store it in the hard drive. Everything in the hard drive is 'scratched' into it like a record. If you delete a file, that part of the disk is 'smoothed' as best as it can. If you upload another file, you might corrupt/ruin the image/pdf. Think of the smoothing like recording a football game over an old VHS of Winne the Pooh. If you have any other questions, please ask by commenting on this answer!
When you are creating a website, you will usually need to add details to the website. If you're coding a website as HTML, you always have to make sure your code is correct. If one thing is a mess up, you have to start the whole thing all over again.
