However since you don't know which memory banks these files were in, chances are you've probably deleted bits of data from all over the place, so the next time you want to install something on your computer, anything you install will be stored in bits that are all over the physical harddrive. The computer now has to work harder to piece all of these bits together by jumping around. This can overtime slow down your computer very noticeably.
To correct for this, it's a good idea to defragment your disk drive from time to time so that all the relevant data is once again assembled consecutively to avoid the extra effort, which helps to speed up whatever process you're running. If you're on a Windows platform, you can defragment by clicking Start -> Run -> dfrgui, or it should be under Accessories under System Tools.
Run the program and it will analyze and defragment your computer for you. The best way to do it is overnight when you're a sleep because at times this process can take over 2-6 hours, depending on your CPU speed and the amount of memory you have available and have used. Hope this helps.
when you download a file be it music movie game application or other it uses space on your hard drive
because ur harddrive is in constant use the arm inside it is all over the place so to save time it just plops the info anywer it finds a free sector
when your hard drive becomes 80% full you will start to notice a drop in the speed of your computer loading things ths is because the drive has to peice together all the bits of the file you are trying to load
when you defragment the program reads the files on your computer and puts all the bits side by side thus making a complete file and helping your pc and hard drive run faster