Total Lack of Wired and Wireless Internet

I have been having this problem for a while now, basically I have two computers I use, this one that connects fine to both the wired and wireless, and this desktop one here I recently put a Radeon HD 6450 Graphics card into the system, I worked with my dad to initally get the card into the correct slot, he even removed the modem card (though I put it back shortly after I discovered it wouldn't connect to the internet to see if that did anything, it didn't) and we put the card in and put all the parts back on, shortly after hooking everything up properly I discover he system won't connect to the internet, it cannot detect the wireless and reads the ethernet cord as a public network and will not connect, now of course for some reason the graphics card did not come with a disc to install the drivers so I had to try several different things, to no avail.

Now later I got my hands on a GeForce GTX 650 Graphics card and I was able to set that up properly, but the disc for some reason needs to connect to the internet to install the drivers for whatever the reason

Now I get a sinking suspision that when my dad removed the dial up modem card from the machine, that messed something up, but I put it back and nothing changed

I even tried re installing windows, and that didn't help either, so I'm stuck with a useless computer at the current time


One peculiar thing though, when I put the Radeon Card into the computer and turned it on, my anitviurs software disappeared, it was just gone, and I really don't understand why that happenned

The antivirus software was Verizon McAfee

and of course with the re installing of windows on the computer it would have been gone anyway, I just am at wits end with this machine

If anyone has any advice I would appreciate it

from what I've tried disabling and re enabling the adapter and that has done nothing

I'm just totally lost and I'm starting to thing some part of the computer is shot at this point.

*Edit*

The modem card thing my dad originally removed was some card thats not used anymore, seemingly for dial up or something since the one end of the card has where you'd plug in a phone cord, but like I said we put the card back in and there was no change at all