Last Known Good Configuration - how to find delta to current config?

Question

My Windows 7 Professional SP1 system has a BSOD after loggin on and waiting for 1 to 5 seconds. The problem does not arise with the 'Last Known Good Configuration' (LKGC) that can be chosen from the F8-Boot menu.

As i did not knowingly change anything on system level in the last weeks, i'd like to know what is going wrong in the current configuration. I enabled boot logging, but was not able to ascertain any specific points of failure.

What i'd like to do is run a sort of diff between the current config and the LKGC to at least see what changed between then and now. Does anybody know how to do that efficiently? The LKGC is really working (hours of use) while the BSODing config fails every time (10/10, never more than a few seconds from showing after-login desktop to BSOD)

I already checked the RAM and SSD (plus the HDD that is D:) and additionally ran a utility from the manufacturer of the laptop to check for other hardware issues. No problems found. The problem occurs on mains-energy-only (bat removed) and on battery.

Answer 1

I appreciate your intention, but you are approaching this in a less than optimal way. What you are asking to do is to compare two copies of your registry. One version is the LKGC which is a copy of your registry immediately after the Windows operating system completes the boot process successfully. And, one AFTER the computer starts the BSoD issue. While you CAN do this, you are likely to not understand the possibly hundreds or thousands of changes that occur in the registry and it will be nothing less than tedious.

What you describe is a pretty straightforward troubleshooting process.

First, with any blue screen, you need to gather the information for the blue screen so you know what type of issue you are looking at.

To do so, start your computer using the F8 Advanced Boot Options Menu item called "Disable automatic restart on system failure." When the computer blue screens it will stop at a point where you can see what information is provided. This detail is pertinent to your troubleshooting steps and can point you in the right direction. Take a picture of it and edit your question with this info or open a new question in relation to it.

If you want to do more in-depth analysis on the blue screen (which has limited value) you can use a tool like BlueScreenView or WhoCrashed. And, using these tools assumes that your operating system actual boots and runs stable long enough to run the tool.

Second, most blue screens are hardware related.

Therefore, regardless of your assumptions about when the problem occurs or why, you need to test all the basics and make sure your computer is in good health. A Windows 7 computer is likely quite old, and running on a hard drive. Hard drives fail, motherboards get leaky capacitors, memory develops bad connections, and fans and heatsinks clog and fail. You need to create some bootable diagnostic disks to test your system hardware and do some basic maintenance.

1. Inspect your computer

If this is a desktop, carefully open the side panel so you can view and access the hardware inside. If it is a laptop, look for an access panel on the bottom of the laptop where you can hopefully access the RAM modules. Look for Leaky Capacitors on your desktop motherboard. Inspect the fans and heatsinks. Use compressed air to clean things out and make sure any fans you can see or access are spinning properly and air is moving.

2. Test your memory

   I would recommend creating a MemTest86+ boot disk. Once booted and testing, use the plastic end of a screwdriver to gently tap the memory modules of your desktop or laptop computer. Let the tests complete through 1 or 2 passes. If there are any crashes or errors, reseat your RAM and test again. It may also be good to purchase Electronic Contact Cleaner to spray both the RAM slots and contacts of the RAM modules if you continue to have trouble with bad connections.

3. Test your hard drive

Hard drives fail and develop bad sectors over time. These bad sectors will corrupt files. The symptoms of this are numerous and varied, including BSoDs. The preferred method is to use a "Long Test" or "Surface Scan" on any number of tools. You can use tools provided by the manufacturer of your hard drive. You can also use open source products such as MHDD. The simplest way for most home users would probably be to use HDDScan from within Windows if it will stay running long enough for you. Careful to only use "non-destructive" tests on your drive. If bad sectors are discovered then the drive is most likely failing, this is the cause of your problem, and it is time to rescue your data immediately and consider replacing the drive and reloading the OS, or replacing the computer.

Third, troubleshoot the problematic application or service.

The problem you describe happens AFTER the computer works properly with a last known good configuration. This means that a change is occurring AFTER the state of the last known good configuration. Barring hardware issues, this is probably an update that is installing. A driver update, security update, malware, etc. To eliminate this issue, AFTER you eliminate hardware issues, use a clean boot troubleshooting process.

This is a process of elimination. First you will disable all non-microsoft services and startup items in msconfig and see if the problem persists. If not, you will enable services and startup items in blocks until you have narrowed down which service or application is causing the issue. Once identified, you can address the problem with that service or application. You can post a new question about that, at that time.