I just finished my first build and got my first fatal error. What should I check if I get a Fatal Error message, Chassis Intrusion. Im running Q6600, bfg9600gt, corsair 520hx psu, 4gb 800 ram, seagate 500gb 7200.11, samsung dvd/rw. In an Antec Solo case.

Don't worry about it.  Some MBs have a feature to detect if someone has opened up the case since the last reboot and report that "Chassis Intrusion".  You may be able to deactivate the checking in the BIOS.