java command line error opening registry key 'SoftwareJavaSoftJava Runtime Environment' java.dll

C:Usershuxxxxchan>java
Error: opening registry key 'SoftwareJavaSoftJava Runtime Environment'
Error: could not find java.dll
Error: Could not find Java SE Runtime Environment.

solution:

http://stackoverflow.com/questions/6362037/java-error-opening-registry-key

I had a similar problem. I had installed JDK7 update 1 but couldn't use it (probably because I found a JRE6 that I deleted after installing JDK7). Uninstalling JDK7 was impossible. The solution was to add the JRE registry entries by hand.

[HKEY_LOCAL_MACHINESOFTWAREJavaSoftJava RuntimeEnvironment]"CurrentVersion"="1.7"[HKEY_LOCAL_MACHINESOFTWAREJavaSoftJava RuntimeEnvironment1.7]"JavaHome"="C:\Program Files\Java\jre7""RuntimeLib"="C:\Program Files\Java\jre7\bin\client\jvm.dll"[HKEY_LOCAL_MACHINESOFTWAREJavaSoftJava RuntimeEnvironment1.7.0_01]"JavaHome"="C:\Program Files\Java\jre7""RuntimeLib"="C:\Program Files\Java\jre7\bin\client\jvm.dll"

You'll have to adjust the above to your own directories and version.

Make sure you remove any java.exe, javaw.exe and javaws.exe from your WindowsSystem32 folder and if you have an x64 system (Win 7 64 bits) also do the same under WindowsSysWOW64.