I got the following error while trying sqldeveloper though I have the jvm.dll file in the required location. All I had to do was to install 32 bit jdk and all went well.
Looks like sqldeveloper has issue with 64 bit jdk.
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Oracle SQL Developer
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Unable to launch the Java Virtual Machine
Located at path:
C:\Program Files\Java\jdk1.7.0_02\jre\bin\server\jvm.dll
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