I had reinstalled knoppix to hd with some 10-20 or 30 errors. To check them what should I do ?? How to fix the same ??

Yesterday, I ran apt-get update and updated fully . How to check whether my os is problem/error free or how to upgrade to knoppix 3.8 or 4.0 from debian repositories. I think its apt-get -u dist-upgrade ......

Regards and thanks in advance...