The following procedure should be followed with this type of error:
1) Leave your computer switched on, try Java installation and wait for error.
2) When error occurs, put shoes on and walk to garden shed
3) Return with a very large hammer
4) Fix the error with the hammer
Lol only joking.
After researching your problem, try downloading this http://forums.whatthetech.com/index.php?s=9e36c6cf27e257754191b6647e94782a&act=attach&type=post&id=7137
Extract and run the .bat file, if you are using W7 or vista you must right click and run as administrator. You should now be able to install Java with no issue
The problem is the registry files still exist and windows installer thinks you already have it on your machine
Let me know if it works or not