Hello, how to resolve the widows 7 is not shuting down some times it take toolong time
More aboutwindows shutdown problem
As xtreme5 said - do a full scan using >1 scanners (e.g. avg free, spybot, mbam), and, have a look at what you have running in the background - your system may need it's annual bloatware prunning. Then re-run the scanners.