Let me google that for you. Have you heard of google? it is a really neat, dude!. It allows you to search for things on the internet and find answers for yourself, instead of annoying others with stupid questions. Try it!
For example, you could type "free chess game analysis"
See a demonstration here:
http://www.lmgtfy.com/?q=chess+game+analysis+free+software
Good luck, dude!
Being a non-premium member i get only one computer analysis per week. Is there any software which do excellent analysis, explaining me my inaccuracies,blunders and mistakes and tell me my as well as my opponent mistakes?.