Why wont my internet work?

So I reformatted my computer. I run Windows XP Pro and this is the deal. I bought all the computer parts from newegg.com and built the computer myself, i installed XP, and ran all my CD's for the motherboard, video card, etc. It ran great for months and then i noticed a slight decrease in performance and decided to reformat. I got windows working and I installed my software using the same disks but my internet wont work this time. I've tried firefox, internet explorer, and MSN couldnt connect either. Under network connections it shows the 1394 Connection and has no X. So I'm sure theres no cables unplugged but nothing will work. Should I try installing a third party ethernet driver or what?

There was one thing that happened during my reformmating that may have done something. I got to the point of putting in the product key and realized i couldnt use tab to hit next i needed a mouse so i had to turn it off and back on and this time i ran into some problems deleting and making a new partition. it said that my disk may be corrupted. But i tried again and instead of deleting it i overwrote the files and it installed, kinda. I started it up and half of windows was missing! the start menu had half the crap it should have, and msconfig didnt even work. so i ran the repair feature on the xp disk and that worked great. Everything works like it did before except my internet. Any Ideas?

|||My feeling is that if you go to device manager and look in the network adapters section you will find that there is a prob with the NIC. Prob a driver issue. Trying right clicking on it and going to properties then selecting reinstall driver.|||I had this same problem with my other computer, whenever things get messy I reformat and then something will magically break down with no intent of working again, much like my old HDD and Disc Drives when I transfered them from my old computer. Buy the 15$ 3rd Party PCI ethernet because machines will always break down just to piss you off|||try to check your internet settings... and check if it is DISABLED?!|||well im no computer expert like you but my answer would just be simply computers are unreliable. they crash, they dont work correctly all of the time, and programs only sometimes make a computer worse then it already is. but fixing a computer on ur own thats pretty nice. but i would have just bought one and been fine with it no matter if it were windows xp or vista all that matters to me is if my computer works like it should and im fine with that:)|||I have no Idea, but did you make sure, you have installed LAN drivers? and also Modem drivers? and then make a new conection and try conecting. Best wishes Samuel