Rescue data from your computer

No backup and your computer won’t start? Not a problem, according to Microsoft – at least, not if you’re using Windows Vista, where the built-in Startup Repair Tool will put things right.

Simply boot the computer from the Vista DVD and you can solve start-up problems with a few mouse clicks. But Vista’s not here yet. So, we’ve put together a collection of tips for rescuing your PC.

XP: Nothing works any more
If Windows won’t start properly, the first thing to do is to see if you can boot in another mode. Turn on the PC and, after the Power on self test (Post), keep the F8 key pressed. XP will then offer two helpful start-up options – ‘Last known good configuration’ and ‘Safe mode’.

Try the ‘Last known good configuration’ option first. This reloads a configuration for Windows, including drivers, that is known to be working. XP stores these collections of valid configurations, known as control sets, in the Registry branch HKey_Local_Machine\System.

The set that will be reinstalled is contained in Select\LastKnownGood. This can fix the damage if a simple Registry change has caused problems, and it can help sort out blue-screen errors.

Be careful though: the ‘Last known good configuration’ is not a magic cure-all. It can’t repair a damaged user profile or corrupted start files. The biggest problem with this method is that Windows is not bothered about what happens after start-up. As long as the system starts, the previous ‘Last known good’ settings will be overwritten immediately.

Safe and sound
In Safe mode, Windows loads only the drivers and services that are absolutely necessary. If your system has become unstable, then you can usually start to repair things in this mode.

The relevant Registry key is HKLM\ System\CurrentControlSet\Control\ SafeBoot, with the subkeys Minimal and Network. In Safe mode, you can reverse a driver update in just a few steps:

Step 1: Click on Start/Run. Enter devmgmt.msc.

Step 2: Click on the device with the problem driver. Select Properties from context menu.

Step 3: Click on Drivers tab. Then click on Installed Drivers.

Step 4: Confirm overwriting of current driver with previous version.

It’s also handy to know you can run the system restore function in Safe mode, and roll XP back to roughly the state before a program was installed. To do this, Windows doesn’t save a complete system image, but sets up what are known as Restore Points.

What exactly is saved is specified in the filelist.xml file in the Windows\system32\ Restore folder. You can restore the operating system to a previous condition, but your own work, such as Word files or emails, will remain as is.

XP creates restore points automatically whenever you install software (installation restore points), at regular intervals (system check restore points) and after Windows Updates (system update restore points). You can use Safe Mode to select a specific restore point to use to rescue your PC.

Step 1: Log on as an Administrator in Safe mode.

Step 2: Click on Start/Programs/Accessories/ System Tools/System Restore. Select the option Restore my computer to an earlier time. Click on Next.

Step 3: Select the restore point you wish to use from the list. Click twice on Next.

Using restore points is more complicated in those cases where Windows XP has not got as far as loading the GUI before giving up. If that happens, you can use the shell command rstrui.

Boot up holding down F8, choose the option to start in Safe mode with a command prompt and log on as an Administrator. Change to the Windows directory under system32\restore, and start the system restoration GUI using the command rstrui.exe.