I bought a second hand machine with Win7 Ultimate Sp1 64 bit preinstalled. I tried to install a printer driver for an Epson printer combo, but failed. A technician at the Epson workshop checked and said that the Win7 was faulty, because it could not detect any external device. Since the machine did not come with an installation disk, I cannot reinstall Win7. Is there any way to repair the problem in the OS without buying a disk?
That's an odd kind of failure for Windows. Starting over with a new Windows install is a lot of work and there is always a chance that the Epson tech got it wrong. Before you reinstall Windows, I would check a few things just on the chance that Windows might not be the problem.
- If the printer is connected by a USB cable, the Epson driver needs to be installed before the printer is connected or it won't find it. If you are not certain that you waited to connect the printer, disconnect the USB cable, uninstall the Epson driver, reinstall the driver, and wait to connect the printer until it prompts for it. I would do this anyway even if you originally waited to connect the printer. Stuff sometimes happens when drivers are loaded and doing it over can be a benign fix.
- Try a different USB cable on the chance that the problem is a bad cable.
- Verify that the issue is not a USB problem if that is how the printer is connected. If you are connecting the printer through a USB hub, try plugging the USB cable directly into a connector on the computer (even if you have to disconnect something else temporarily just to test this). USB hubs are problem prone in general and printers often have problems connecting through them. And, of course, wait to plug it in per the first bullet. Try a different USB port, particularly in another location on the machine. If the computer is a desktop, there may be several USB ports in back and another couple in front or on top. Try one of the ports in another location on the machine. Verify that the USB port is working by plugging another device into it, like a thumb drive.
- Try to verify that the printer is not defective. Try to install it on another computer--a fast thing to test and undo. If that isn't practical, try to run a self-test on the printer. Many printers come with this feature. Without it necessarily being connected to a computer, you turn it on, typically while holding down one of the buttons (need to check the manual to find the procedure for your particular printer). This causes the printer to run some diagnostics and print a page of results. If the printer doesn't have that feature, many have a "demo" mode where you similarly turn it on while holding down a particular button. This mode generates a sample printed page.
Before you reinstall Windows, if something is corrupted, you may be able to repair it. From the Windows Start button menu, use the Run window to run the command SCF /SCANNOW (you don't need caps). If you did not create a repair boot disk, do that and see if you can repair the problem without reinstalling windows. There are also a bunch of free third party repair tools; just search this forum and google.
If it is necessary to reinstall Windows, try the upgrade in place option, which is the most benign reinstall. It will preserve as much of your stuff as possible. See this link: http://support.microsoft.com/kb/2255099
If you get to the point where you have to do a complete Windows reinstall, most computers with Windows pre-installed come with a recovery partition instead of a Windows install DVD. You should be able to use that to reinstall the identical version of Windows, including hardware-specific drivers that came with the computer. That does not require the license key if you don't have it (but see TrainableMan's reply about how to extract the key if you do need it, and that is something you should do just in case before you start over-writing Windows). Using a generic Windows iso is the very last option to do because it will not contain drivers specific to the hardware in your computer (the OEM Windows install is customized).