Make sure both options have a checkmark beside them and then click on "Start" but since the C drive is in use we will have to schedule this disk check the next time Windows is restarted.
Then click on Memory Diagnostic Tool and continue through the uac nag screens and you will end up with this option.
I suggest to go ahead and click Restart now and check for problems. Windows will restart the computer automatically and begin testing the computer memory. The Memory Diagnostic Tool has three modes : Basic, Standard and Extended tests which can be accessed by pressing "F1" during the test and then "F10" to apply(by default Windows will perform a STANDARD test). After all the tests have been completed Windows will display the results of the test after you log on.