a noob question about computers getting worn out

[xxThe_Lebowskixx]

i have a dell inspiron 9300 and it seems to have gotten much slower since i initially purchased it despite the fact that i have almost nothing on the computer except for poker software. i must have a ton of free space and i use the computer solely for the internet, movies and music.

why is it slower now? do computers get worn out after awhile?

will uninstalling everything on my computer and then reinstalling it make it faster? how do i do this?