If your computer is acting strangely, the problem could be in your hard drive. Western Digital, a hard drive manufacturer, has software available to test any brand. The software first uses external commands to test drives. Then it calls on drives' self-test features.
Only late model drives are likely to have these features, known as Self-Monitoring Analysis and Reporting Technology. SMART is an industry standard used by most manufacturers. The tests will give you the serial and model numbers of the drive. They also will report on the drive's condition. The software can be found here.
http://support.wdc.com/dlg