If you know your machine is in good shape.
Turn off system restore and reboot.
Then turn it back on.
That will rid your drive of all of the previous restore points.
As for the unpacking of files what I do is unpack them into the same folder all of the time. Install the prog. then delete the folder.
In the user folders look for deleted prog folders and delete them as they alway leave something behind.
Also while there check the desktop folders of the different users.
Many people put programs, movies, and all sorts of other huge files on their desktop instead of into a folder and that causes a MAJOR drain on the system because the system keeps them in memory instead of a simple link to their location.