My Windows XP computer shows a blank screen and an error message saying, “Please reinstall shdocvw.dll.” I don’t know what it is or where to get it.
Shdocvw.dii or Shdocvw.dll?
Before we move forward, I noticed the file extension .dii in your question. Let’s capitalize that, shall we? DII looks remarkably similar to DLL, doesn’t it? I believe the error is really a DLL error, though I’m always a bit unnerved when I see .dii errors. Why? Because malware makers commonly give their programs legitimate looking names in order to trick users. Hopefully, it’s really a DLL file, because those are usually easy enough to deal with.
What is Shdocvw.DLL?
The Shdocvw.dll file is a Shell Document Object and Control Library file that is required by Windows. It is involved in displaying your folders and, as you’ve discovered, Windows won’t work without it.
Is the black screen a window? Can you see any icons? Can you access the Start button? If so, you can use System Restore or the System File Checker utility using traditional means. If not, it’s a bit trickier.
Try System Restore from a Command Prompt
Is the black screen an actual command prompt screen? That is can you enter commands after the C:\ prompt? If so, you can try running a few commands such as System Restore and System File Checker. If not, try rebooting while pressing the F8 key in order to get into the Safe Mode choices screen. Pick Safe Mode with Command Prompt. Enter:
%systemroot%\system32\restore\rstrui.exe
Note that you’ll replace %systemroot% with the appropriate location of Windows such as:
C:\Windows\system32\restore\rstrui.exe
Try System File Checker
If you do not have a restore point, the System File Checker is the next tool to try. You will need your Windows installation discs because the System File Checker will scan your system for damaged or missing files, such as the shdocvw.dll file, and replace them with original copies from the disc. Once again, get into Safe Mode with a Command Prompt. Type in:
sfc \scannow (note the extra space before the ‘\’and press enter once typed)
Try Windows XP Repair
What if you can’t get to a command prompt? Not to worry, Windows XP’s installation discs also come with a repair Windows XP option. Insert the Windows XP disc in the drive and reboot your computer (you may need to change the boot order in BIOS). You’ll see a Windows Setup screen with several choices, one of which is “To setup Windows now, press Enter.” Press Enter. Don’t worry, we won’t be reinstalling Windows. DO NOT SELECT THE RECOVERY CONSOLE REPAIR OPTION DESPITE ITS FRIENDLY SOUNDING NAME.
Accept the license agreement and then choose the Windows XP installation on your computer and press the R key. Hang tight and let Windows do its thing. It will look like it’s reinstalling, but don’t worry - it’s only repairing. Once complete, you’ll be asked to activate Windows. You may want to postpone activation until you’ve enabled your firewall to protect against worms.
After performing the repair, go to Windows Update and update your operating system as your service packs and other security patches will likely have been removed by the repair.

DLL errors mean that something is wrong with the registry - the registry contains information and the settings for basically everything on your system. This includes the hardware, software, preferences and users. Your operating system uses information from the registry continually while it is running. DLL errors usually occur when there is malware or a virus or a program was installed or removed improperly.