A well and in good condition PC will not hang up running scandisk.

Your first priority is to make sure that nothing you can't lose has a copy elsewhere on CDR or what backup you use.

After this, check the Shutdown Article at http://www.aumha.org/articles.htm if you are having issues shutting down proper.

Next boot SAFE MODE and run the scan again. SAFE MODE must complete or you need to fix the machine.