Hi,
Have tried the latest JRE update 51?
Recommended Version 8 Update 51
http://java.com/en/download/manual.jsp
If it still fail to install, recommend you remove all old version of JAVA and reinstall again.
Why should I uninstall older versions of Java from my system?
http://java.com/en/download/faq/remove_olderversions.xml
If we still fail to get this done, please capture the system events via Process monitor when reproing this issue and find if there is any error during installation.
Process Monitor v3.05
http://technet.microsoft.com/en-us/sysinternals/bb896645.aspx
How to use, please refer to this article:
Using Process Monitor to capture system events
http://www.sophos.com/en-us/support/knowledgebase/119038.aspx