When I try to do java from commands prompt in windows I am getting this error :
Error loading: C:\Program Files\Java\jre6\bin\client\jvm.dll
The dll is there and it is fine.
It sounds like your Java default installation has been corrupted in one way or another.
I would suggest uninstalling and go to http://java.com/en/ to get the browser to auto-detect and install the correct files for your system.