I don't exactly know your problem
but I've some Sugessions:
1 - When You uninstalled j2sdk and eclipse , do U uninstall eclipse or remove
it completly??
I think complete remove would do it effictivly. (But please continue
reading).

2 - I download eclipse from the official website , It doesn't require
installation any more.
only jdk required!, try this!

3 - for java developing I prefer netbeans (the new 6.0 released :)) )
download it from http://netbeans.org