Scan faster by deleting your temporary files before you begin. The easiest way to do so is to use the Windows Disk Cleanup Tool. Find it using the search box in the Start (Windows) menu or travel from Start–>All Programs–>Accessories–>System Tools–>Disk Cleanup. It will take a few moments to calculate disk space and will then present a check/uncheck menu of files to delete. Check the appropriate boxes and if you have any questions about what certain files might be click the file name once and the Disk Cleanup will provide a description and often a recommendation.
Deleting these files will free up disk space and, as an added benefit, can also get rid of a few types of malware.