Disk Doctor fails to find bad blocks while System Event Log shows many

I am obviously having disk problems on my HP which is about a year old.  The windows 8.1 event log shows many many disk block errors.  Running DSKCHK shows no problems.  I read in a forum that Norton Disk Doctor did a better job and so I just bought it.  But nope, it shows no disk problems while the event log shows disk block errors at the exact time disk doctor was running.  So what gives?  If I really have a 30 day trial I might as well send this back because it is pretty worthless.  It apparently is just a pretty front end for dskchk.