Based on my 22 years experience as sysadmin, I recommend you the free tools for forensic analysis and systems assessment:

Powershell windows forensics: https://github.com/Invoke-IR/PowerForensics

Powershell windows forensics: https://github.com/gfoss/PSRecon

Powershell windows forensics: https://github.com/davehull/Kansa

http://www.powershellmagazine.com/2014/07/18/kansa-a-powershell-based-incident-response-framework/

Timeline Tools

RegRipper

FTK Imager

Volatility: http://www.volatilityfoundation.org/

http://www.crowdstrike.com/community-tools/index.html

McAfee foundstone free tools: http://www.mcafee.com/us/downloads/free-tools/index.aspx

http://www.truesec.com/tools/

http://www.joeware.net

http://helgeklein.com/setacl/

http://www.microsoft.com/sysinternals

http://www.systemtools.com

http://www.netikus.net

http://www.insecure.org  and http://sectools.org

http://joshuadlewis.blogspot.fr/2014/10/advanced-threat-detection-with-sysmon_74.html