Internet doesn't work in REV 1

Hi, I am new and nooby to all of this. I've recently installed leopard on my tiger installation, and the only way I am able to boot up leopard is through safe boot/ safe mode. Could the no internet problem be because i am safe booting. I am connecting through LAN (no wifi) and the network diagnosic wizard says that it's not working, not detecting this. Also could someone explain what the kexts are, and how to use them. Like I said i am a noob, so please speak slowly and carefully (in other words if you can, use great detail.) I don't think I can give you my specs because I don't know where to find everyone of them. My computer model is HP Media center TV PC m1800n. The link below is my pc's support page hopefully you can find your specs there. (I am sorry if this makes you think I am rude, I am not trying to be) Oh, I have installed this on a seperate IDE harddrive, but my system is still AMD

http://h10025.www1.hp.com/ewfrf/wc/product?product=3440… ↗

thanks so much... Zephyroth ROCKS!