1)Download jdk-6u20-windows-i586
2)Install jdk-6u20-windows-i586
3)To make sure that Windows can find the Java compiler and interpreter:
• Select Start -> Computer -> System Properties -> Advanced system settings -> Environment Variables -> System variables -> Path.
• [ In Vista, select Start -> My Computer -> Properties -> Advanced -> Environment Variables -> System variables -> PATH. ]
• [ In Windows XP, Select Start -> Control Panel -> System -> Advanced -> Environment Variables -> System variables -> PATH. ]
• [ In Windows 7, Select Start -> Control Panel -> System -> Advanced system settings -> Environment Variables -> System variables -> PATH. ]
4)Paste C:\Program Files\Java\jdk1.6.0_20\bin; to the beginning of the Variable value
5)Click OK
6)This could solve your problem very well.
Please read my article on how to install How to Install Eclipse Ide for Java Developers
http://computersight.com/programming/how-to-install-eclipse-ide-for-java-developers/