why is my computer so slow?

well there could be alote of reasons you probably have many heavy programs that uses much space on your computer you also have to consider what computer you have what processor, how much memories and so on i know from my experiance that i had a bit old computer that could not handle all of my heavy programs and that mde him so slow i could not have worked on him can you state what computer and components you have?

well,u have to post your pc configuration for receive a good answer :)

your computer may be slow because there are too many things on it and using up needed space and it makes it slow .. or maybe its just your computer .. you should disk clean it and defrage it every day or a few times a week

You should remove useless startup programs, check for spywares and use a non-resource hungry anti-virus.