P4C800Deluxe High Temps?

I just put together my first pc. Its a Asus P4C800Deluxe with a 3.0ghz cpu in a Antec P160 case. Looks like it would have excelllent airflow. My problem is it will just reboot on its own. Is this because the cpu is getting to hot, thought I would install a new cpu fan, someone had told me that the cpu with the 800fsb runs really hot that if I didn't keep it cool it would burn up the chip? What kind of temps are normal with this setup? I purchased a Thermaltake P4 Spark 7+, hope I did right. Till I git new fan installed I'm leaving her sit.This is all new to me. Thanx again to all the members, I have gained alot of knowledge thru you!