This bug leads the machine into a critical condition.
When the java install folder is deleted manually without a doing a proper uninstallation, it leads to a critical condition, from where it is not possible to install/uninstall Java into the same machine.

Steps :
1) Install JRE (latest one, 6u10-b26 PIT)
2) Go to the installation folder (say the default location, Program Files\Java\jre6) and delete the folder jre6
3) Try to install the same java in that same machine.

It is not possible to install the same Java again in that machine.

Ideally, it sould allow to reinstall the same java, even though the uninstallation was not proper (that is what the user experinece with other application install/uninstall)




As a workaround, I tried the folloing actions on that machine but it did not help

- Trying uninstalling Java from Control Panel -> Add Remove program
   > It gives fatal error
- Trying installing different version of java and then uninstalling (thinking it can clean the previous registry entries while uninstallation)
   > It is possible to install/uninstall other older versions of java (6u4 | 5 etc)
- Cleaning the registry entry manually(HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft)
- Restarting the machine.

Finally, I used a registry cleaner tool (Windows Install Clean Up)to clean the registry and then could install the same java on that machine.