Network Adapter Dissappeared after an update

My daughter has a Dell Inspiron 2600 laptop, and just a few days ago, signed up with Charter ISP in Carrollton, Georgia. It is a cable connection through a USRobotics modem that I gave her. All was ok for a few days. She states that today(3 days later) she suddenly lost her ability to connect to the net. I live 80 miles away in the Atlanta area, so I can't fix it without being there. She states that she spent some time on the phone with Charter tech supp, and she now knows that the network adapter from within the device manager has disappeared.
She tried system restore with no luck. She doesn't have a restore disk, but can probably get online from her place of work if downloading a new driver is necessary. Is it? Or can she simply try and use add new hardware from within the control panel? Her OS is XP home(I think) with SP2 installed. She sates that her connection went missing after some automatic update-though she's not sure whether it was a Windows update or AVG, SPYBOT, ADAWARE, etc.
Can anyone help? I have personally never used system restore. She tried it, and there are two options somewhere along the way, she says. The first one she tried didn't work, and she hasn't tried the other one yet. Thanks.

 

If there is no sign of any unidentified hardware in Device Manager you could run the Add New Hardware wizard. If there is an unidentified piece of hardware ( "the drivers for this device are not installed "), it may be better to uninstall it, reboot and go through the hardware wizard when Windows boots up.

If the adapter had a good set of drivers installed originally, once you uninstall it, if Plug and Play is operating correctly Windows should identify the device and install the drivers automatically. If not, she should update her drivers, beginning with any Chipset updates, at the Dell website.

How to use System Restore:
http://support.microsoft.com/kb/306084/en-us
Matt

 

Thank you, Mattman. I'll call her later today and see if we can't walk through it together.

 

Network adapter still missing from a Dell Inspiron 2600

I went to Dell's site and downloaded the R49651.exe file which identifies itself under Network Drivers as 3COM 3C920 Integrated LAN. I then emailed it to my daughter's place of work. She took it home on a USB device, executed it, and the installation wizard states that the installation was successful. The LAN device still can't be found under the device manager. What did she do wrong?
Simply using the ADD NEW Hardware option doesn't show a network adapter as an option. This is definitely a Dell Inspiron 2600, Service Tag G3SCC21. How can I positively confirm that the integrated LAN is indeed the 3COM 3C920, and that she isn't trying to install a driver for a device that is in fact something else?
As I said, she was online for about 3 days, and the LAN device disappeared after a Windows update. I can't say positively which LAN device is installed in the laptop. I'm just going by what support.dell says when I enter either INSPIRON 2600 or the service tag code. Both take me to the same download options.

 

Is System restore meant to restore a problem like this?

My daughter states that she went through the system restore procedure, and arrived at a point where there were two options. She chose one, and it didn't solve her problem. Not ever having used system restore myself, I don't know if the other option, should she try it, would help. Would it?
I should mention that she tried system restore last Thursday or Friday, and the reinstallation of drivers today. So far, no progress.
Any and all hints or directions towards getting her back online woould be greatly appreciated.
Thanks.