Vista is like this. So much protection, you can't maintain your own computer.
Secunia told me the same thing. It is possible. I did it.
From your Help function, enter Change Data Execution Prevention settings
Follow the steps. Make sure the first DEP option is selected.
From your Help function, enter Turn User Account Control on or off
Unselect the option.
I think that's all.
From the Control Panel, uninstall ALL repeat ALL Java related software.
Download and install this program (it's free) CCleaner.
After installing...run the program...
Before the first use, select Options > Advanced and UNCHECK "Only delete files in Windows Temp folder older than 48 hours"
Click on Analyzer...then click on Run Cleaner.
On the left side of the window, click on Registry...click on Scan for issues...click on Fix selected issues.
Now download/install JAVA.