|Why do you want to delete these files, they are quite normal?|
What you have mentioned includes system restore files (that could restore your computer if it goes wrong) and your recycle bin.
On Windows 7 (and Vista) it is best to NOT show hidden files or protected operating system files, then they won't bother you. Go to Control Panel and set them back to hidden (the default). If you let them show you can get desktop.ini files appearing on the desktop itself.
Note that we get a lot of people on here that delete files and then ask us to help get their computers working again. Leave them alone.
Always pop back and let us know the outcome - thanks