On a windows machine, perform the following steps:

1) Install JRE 1.4.2_10
2) Install JRE 1.5.0_05 or Mustang
3) Uninstall JRE 1.4.2_10

The HKLM\Software\JavaSoft\Java Runtime Environment\1.4 is still there after uninstallation of JRE 1.4.2_10.

This problem existed since JRE 1.4.2 but manifested differently there; the values of the sub-keys under the above mentioned key are different.