Wireless/Ethernet Adapter MISSING after re-installing OS and drivers

I have a Dell Latitude D600 that was an old corporate computer that I purchased online, just to d/l stuff and watch movies on my TV. As such, it didn't come with any backup disks, etc. Just a generic folder of a bunch of Dell and other drivers on it.

So, I was having some issues with the computer (running slow, shutting down randomly, etc), so I d/l'ed a stripped version of Win XP Performance and re-installed it on my machine.

Once I reinstalled it and tried to load the proper drivers, everything ran fine for a bit, then it started 'acting up' again...so I d/l'ed another, full version of XP (SP3), thinking that the stripped version might have been screwy.

Here's where the fun begins......I went on the Dell website and put in my service tag, in order to download the proper drivers, which I did from my desktop and transferred to my laptop. BUT, even after I install the drivers and computer re-boots, it acts as if I don't have ANY hardware installed. The device manager doesn't even show them as being on there. What's even odder is I try and try again to load the drivers and sometimes, they will work....until computer shuts down and they are gone again.

You guys are my last hope....I'm assume that the hardware is fine, as it ran perfectly before I messed around and re-installed a new version of the OS. I have worked on this thing for about 2 weeks and I'm nearing the end of my rope and about to burn this sucker if I can't figure out what's going on.

I really haven't fooled around with the BIOS much, as I don't really know how to configure it. My network adapters are this (as listed by Dell):

Dell Wireless 1350 WLAN PC Card
Broadcom 570x Gigabit Integrated Controller

I suppose it is a possiblity that the drivers/adapters that are listed by Dell aren't the actual once on the computer, but I have no clue how to find that out, because they aren't listed! I have tried every driver that is in the folder that came with the computer (trust me, it's about 30) for the wireless and ehternet and like I said, sometimes it worked, but once I rebooted it, it was back to being a ghost.

Thanks in advance and sorry for the long post....just trying to be as through as possible...