Change any passwords ASAP... after doing the below.
A couple of decades on you you whipersnapper!
Without the Discs you can't Restore or do much.
If you call AppleCre with the Serial# handy, you can get Replacement original Discs for free or maybe $30.
Little Snitch, stops/alerts outgoing stuff...
Flashback - Detect and remove the uprising Mac OS X Trojan...
In order to avoid detection, the installer will first look for the presence of some antivirus tools and other utilities that might be present on a power user's system, which according to F-Secure include the following:
If these tools are found, then the malware deletes itself in an attempt to prevent detection by those who have the means and capability to do so. Many malware programs use this behavior, as was seen in others such as the Tsunami malware bot.
This script from F-Secure is the only one I'm currently recommending http://www.f-secure.com/weblog/archives/00002346.html
Open DNS also blocks the FlashBack thing...