You may have problems with hardware you don't even know about – so here's a way to check for these and correct them. I recently had to do a clean install of Windows 7 on a friend's laptop. Easy, right? Boot from the installer disk, and let Windows download all the appropriate drivers.
Not so fast. What if the very network driver, which allows this downloading of the rest of the drivers, wasn't working? That turned out to be the case with my laptop upgrade.
Have Windows automatically fix driver problems
The first thing to try is Windows 7's automated hardware troubleshooter. Click on the Windows button, and type "fix hardware" into the search bar. The top hit should be "Find and fix problems with devices." Click on this. This will start a Wizard entitled Hardware and Devices. Click Next to have it start detecting problems and checking for missing drivers. The troubleshooter will search through all your installed devices, and for each issue it finds, you'll be offered a choice between Apply this fix, or Skip this fix. It's probably a good idea to choose the first, especially if the troubleshooter appears to have found the network driver in the case of our example.
It's not a bad idea to run this feature even when you may think you have no problems, just to make sure. If it works, you'll see notification bubbles at the bottom of the screen saying "Installing device driver software." But in some cases, like mine, the troubleshooter won't be able to get your hardware working, and that message will change to "Device driver software was not successfully installed."
Get the right driver for the right hardware
Next you may think – just go to the laptop maker's site and download the driver. Of course, this requires another computer that is successfully communicating with the network, so you may have to visit a pal. (You may even have thought of that before this point). But often the laptop maker uses several different possible network adapters for even the same laptop model and sub-model. You're basically left to guess which you have. You needn't guess, but finding the answer is far from straightforward. Before you can proceed, you must install one of the vendor's drivers. It may be the right one if you're lucky, but if not, it will enable the next step to determine the actual hardware.
Open Windows 7's System Information window, by typing "System Information" in the Start Menu's search box and clicking on the top found item. This opens a two-panel window, showing an expandable list of Hardware Resources, Components, and Software on the left, and details on the right. Hit the plus sign next to Components, and near the bottom of its list, you'll see a Problem Devices choice. Your nonworking network adapter should be there, named from the nonworking driver you installed.
The key is in the second column: "PNP Device ID." This will show a long string, such as:
We're interested in the four digits or letters following the letters VEN_ and the four following DEV_. Make a note of these and head to your friend's PC with the working Internet connection. You can find the manufacturer name by entering the four digits after VEN in the PCI Database site. Unfortunately, you can only enter the vendor code or the model code, but not both in a single search. Entering the device ID in the second search box shows a list of possible devices, and matching it with the vendor name you found in the first search should do the trick.
In my case, it was enough to know the correct network adaptor vendor and download the driver based on that from the laptop maker's site. I'd originally installed a driver for an Intel adapter, but the process above showed me that my laptop actually had a Realtek device. Running the installer from the laptop maker's support finally got me online, and all the other system drivers needed were detected, downloaded, and installed automatically by Windows 7.