Looks like the existing installation has not been removed using the 'uninstall' program. Given that, please do the following.
a). Stop all servers, left over vm processes running from c:\sun\sdk.
b). Delete c:\sun\sdk and its contents.
c). ** Also delete %SystemRoot%\system32\productregistry file. %SystemRoot% usually points to C:\Windows, but if you have relocated windows install, then please give that path.
HTH
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