Go to Control Panel > Add/Remove Programs, and see if it is there.
If you have older and more vulnerable Java version(s) installed, you need to remove those and update to the latest version:
Download the latest version of Sun Java [Java Runtime Environment (JRE) 6 Update 26].
Choose to download the Windows 7/XP Offline, but, you need to know if your system is 32bit or 64bit:
Click Start, and then click: Run
Click the General tab.
The operating system is displayed as follows:
For a 64-bit version operating system: Windows XP Professional x64 Edition Version < Year> appears under System.
For a 32-bit version operating system: Windows XP Professional Version <Year> appears under System.
When done downloading, go to Control Panel > Add/Remove Programs and uninstall all versions Java/JRE (Sun Java Runtime Environment/J2SE Runtime Environment), and reboot.
Then, click the downloaded jre… file to install the latest Java version, being sure to reboot after.
Retired - Doin' Dis, Dat, and slapping malware.