A link with pictures to get to command prompt (simple but pictures help). http://www.sevenforums.com/tutorials/682-command-prompt-startup.html
Option 1 should work using Shift + F10. If not Option 2 is shown here with detailing pictures. http://www.sevenforums.com/tutorials/668-system-recovery-options.html
From Command Prompt type in diskpart and hit <enter>.
At the new prompt type list disk and hit <enter>.
At the new prompt type select disk 0 and hit <enter>. Note: You should only have one disc listed and my guess is disk 0 (any question please ask).
At the next prompt type clean all and hit enter.
Here is the link with more detailed instructions for diskpart but those are the only necessary commands in most circumstances. I omitted the one at the link for offline to online because I have never seen that situation. http://www.sevenforums.com/tutorials/52129-disk-clean-clean-all-diskpart-command.html
I guess you can tell I like sevenforums.com
This full cleaning is really a zeroing out of the disk it is as thorough as Seatools and should do as much for the disk as there program could. It says about an hour for 320gb but I'm not certain it is that slow anymore.