| Signs of Registry Problems |
How can I determine whether Windows problems are caused by the Registry? Registry corruption can take two forms: either the Registry's database files can be damaged by an errant disk operation, or information can be entered incorrectly, by hand or by a buggy program. No matter what the cause, the result can be a system that won't run, or one that reboots itself over and over. Other signs of Registry corruption or errors could be as follows: Drivers aren't loaded, or they give errors while Windows is booting. Software complains about components that aren't registered or cannot be located. Undesirable programs attempt to run when you log in. Windows does not boot, or it starts up only in Safe mode.
Recovering from a Suspected Registry Problem How do I recover from a Registry problem? If any of the signs of a Registry problem occur just after you install new software or hardware, after you've edited the Registry manually, or after an unexpected and unprotected power loss to the computer, then you might have a Registry problem. Try these fixes in turn, checking after each step to see whether the problem is resolved: 1. | If the problem occurred right after you installed new software, see whether the software manufacturer has released any updates for the software. If an update is available, install the updated software before proceeding. In any case, try reinstalling the software. If that doesn't fix the problem, uninstall it and then reinstall it again. | 2. | If the problem occurred right after installing a new piece of hardware or updating a device driver, try updating the device driver or using the Driver Rollback feature. For information on the Device Rollback, p. 1179. | 3. | Restart Windows, and just before Windows startup screen would appear, or when the Please Select the Operating System to Start message appears, press the F8 key. Select Last Known Good Configuration. Last Known Good uses the previous boot's version of HKEY_LOCAL_CONFIG, so good hardware settings might be preserved there. | 4. | If you get to this point, get professional technical help if it is available. If that's not an option, continue to step 5. | 5. | Use System Restore to try to return to an earlier saved system configuration. For information on the System Restore, p. 1285. | 6. | If none of these fixes solve the problem, or if you can't get Windows started, try starting Windows in Safe mode. Starting this way circumvents many display driver setup problems. If you suspect the problem is caused by the display driver, set Windows to use the Standard VGA driver and restart. Then reinstall your normal graphics adapter (using the most recent updated driver). | 7. | If you have a backup containing the Registry (System State), restore it. This fix should return you to a state where you had a working system. | 8. | Use the Emergency Repair Disk to repair Windows (Repair mode). | 9. | Reinstall Windows in Repair mode. For more information about reinstalling Windows, p. 1282. | 10. | Reinstall Windows in Clean Install mode. This will require you to reinstall all of your applications and reconfigure users, so it's an absolute last resort. |
Tracking Down Errant Startup Programs How do I track down and eliminate startup programs that don't appear in the Start menu but start anyway when I launch Windows? When you log on, Windows examines the Startup folder in your personal Start Menu\Programs folder as well as in the corresponding folder under \Documents and Settings\All Users. In addition, Windows examines the Startup folder in the Start Menu Programs folders of both the user logging in and the All Users folder. Windows also looks in the Registry for values in the following keys: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce The LOCAL_MACHINE enTRies are run for all users, and the CURRENT_USER entries are, of course, specific to each individual user. If you're trying to eliminate a Startup program and can't find it in your own Startup folder, look in the following places: 1. | Look for a shortcut or program in the folder \Documents and Settings\Default User\Start Menu\Programs\Startup. | 2. | Examine SYSTEM.INI in C:\windows. Look for load= or run= lines in the [boot] section. The program might be run from here. | 3. | Examine the Startup folders under Programs in both your Start Menu folder and in the All Users\ Start Menu folder. Right-click your Start button, and select Explore to examine these folders. Note: if your disk uses the NTFS format, you must have Computer Administrator privileges or be a member of the Power Users group to delete an entry from the All Users folder. | 4. | Run Regedit, and browse to key HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion. Look under any subkeys named Run, RunOnce, or RunOnceEx. Check their values for entries that are starting the undesired program. The RunOnce entries are often set by installer programs to complete an installation process after rebooting and are sometimes not eliminated properly. | 5. | Repeat the same process with HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion, again looking under Run, RunOnce, and RunOnceEx. |
NOTE If you can't log in as the affected user, and you suspect that the startup program is run from the HKEY_CURRENT_USER Registry entry, see "Editing Registry Entries for Another User" earlier in this chapter. |