Always a good idea to clean out your temp file every few days or so, especially if you do a lot of progams installing/uninstalling. To do thi manually, just go Start>Run> and type "%temp" (Without the quotes but WITH the percent signs). This will bring up your temp file. This can be quite large, and could easily account for the 251mb of data. To clean it, just Select All the files and hit the delete key. You may notice some files don't delete, but throw up an error dialogue. This is just because they are being used by Windows. - Get rid of all of these and your system will run a bit better.
