Dealing with a Sick Computer



Disclaimer: Before you attempt to do ANYTHING with a sick PC, ask yourself the following two questions:

If the answers are "very valuable" and "not really" then stop at this point and get in professional help! Otherwise you can take your own risk and consider the following suggestions. But remember this comes with no warranty at all.


Some typical problems with fixing a PC, Windows-based in particular, that need to be checked out. The order is important because there is no point in attempting to fix a 'software problem' when the underlying hardware is broken!


#

Problem

Test Options

Comments

1

Hardware fault, the “bulging capacitors of death”, or memory and/or I/O chipset errors.

Rare, but most likely on machines over 4 years old, though not impossible on others.

Sudden crash with Blue Screen Of Death (BSOD) when doing things, or randomly rebooting.

First inspect the PC innards (if possible) for bulging or leaky capacitors on the motherboard.

Try a LINUX boot CD and run the memory test program, see if it can run through at least 2 of the test patterns.

Unlikely, but if found too serious to do anything more. Best to scrap the PC and consider copying data of the hard disk.


Occasionally the PSU has problems, though they tend to die completely.

2

Dying hard disk.

Moderate chance, as failure rate is 1-2% of HDD per year, more if manufacturing fault.

Can be problem of slow/crash, or something Windows reports problems.

Often S.M.A.R.T. is disabled in the PC's BIOS, so try enabling and then use a boot CD and run the tool to check the HDD status first. For example GSmartControl in LINUX.


Can also be checked with the command chkdsk C: /r (for the C: drive, etc) if the host PC is moderately usable.

If HDD is dead, then its new HDD and fresh install, if dying then want to get data off as soon as possible, and before trying to 'fix' the disk.

Professional data recovery is very expensive and probably not a realistic option.

If disk sectors have gone bad, and the user has tried to de-fragment the HDD, chances are the system is going to be very difficult to recover.

3

Virus infestation.

Very likely of the owner has been looking for 'speciality videos' or using file-sharing software.

Slow crappy behaviour, maybe odd BSOD due to infestation.

Need a boot CD with decent anti-virus (in case of root-kit that hides itself or disables AV software).

Removal sometimes works, but often I would be happier with recovered user data scanned, then wipe and re-install everything,

Make sure the Master Boot Record (MBR) is wiped or definitely overwritten with good data in any re-install.

4

Windows shagged with time.

Happens after time of using windows and installing/removing software, and/or patches.

If no AV problems found under (#3), then likely to be general crap.

A re-install from scratch usually works wonders, but is tedious to do.

Backups and CD available? (unlikely)

5

File system corrupted.

Run chkdsk C: /f (reboot usually required) and see what the result are in the 'Application Log' of the Administrative Tools → Event Viewer.

You probably should have run the surface test already (see #2), so the answer should be known!

It is a really good idea to image the HDD to another good HDD and work on that, just in case.
If corruption is very bad, you can try using a LINUX boot CD with the ntfsfix utility utility, but that then relies on Windows working well enough to fix remaining NTFS file system problems afterwards.



NOTES:

(1) The MBR wipe can be done with a LINUX boot CD with the following command for the 1st SATA disk (or similar, find out what /dev/sda or /dev/hda are, etc):

sudo dd if=/dev/zero of=/dev/sda bs=512 count=1

This zeroing of the MBR will destroy any partition data, so the disk will look blank and need to be partitioned and formatted again.

Or use fdisk /mbr under DOS/windows to do the same virus-free setting of the MBR data.

(2) While LINUX has Klam anti-virus, it typically has a lot of false positives (problems that are not real) on a typical windows PC, so best for scanning users' data files only.

A search for 'BitDefender rescue CD' might be just what you need.

AVG sell a 'recovery CD' with AV tools that might be very useful to have, but not obvious on their web site today though...

(3) Most users won't have the original XP or similar CD to fix the system, in fact, most are lucky if they have a “restore CD” which performs a system wipe and install. Dell, for example, usually have a restore partition on the HDD that will do that, so long as the HDD is not broken of course!

If they don't then its too bad, as Microsoft don't sell XP any more. An old PC (more than 3 years or so) won't run Vista, and most likely not “windows 7” either even though it is claimed to require less resources. Drivers for older PC hardware, printers, etc, don't exist in most cases for Vista or '7'. The options are LINUX if they can adapt (i.e. willing to learn and have no special software or games they must have), or a new PC.

(4) They generally won't have backup copies of anything. Often they start by saying there is nothing important on the PC, but then often remember they had photos, home videos, documents or just email address lists.

If HDD dead/dying, or too screwed for any help, then it just too bad. Maybe next time they will take more care with their data...

Trying to recover data is hard, you can use LINUX dd utility to copy a dying disk to new one, with in this example /dev/hda as the old disk and /dev/hdb new disk (but make damn sure you get it the right way round!):

sudo dd if=/dev/hda of=/dev/hdb bs=4k conv=noerror,sync

This will take some 3 hour or more for a couple of hundred GB disk. Then use various NTFS tools to try fixing the copied system. But it slow, and little chance of good results.

(5) They won't have key passwords or user accounts in a safe place. So chances of getting email working are slim unless its a web-mail system they regularly use.

(6) Microsoft provide some detailed information on Troubleshooting Disks and File Systems.


(c) Paul Crawford, 3rd Nob 2011 - All rights reserved.