Troubleshooting Windows 7 : OS Doesn’t Boot After Startup Screen

A few weeks ago, I faced one of the most dreaded things that can happen to Windows – it wouldn’t load after the Windows startup screen. Two weeks prior to this incident, a lightning strike damaged my motherboard’s ethernet controller and then eventually my power supply unit got damaged. Since then I have managed to fix my power supply unit and also bought a new one (currently using the new one). I also bought a new WLAN card from TP-Link which also caused a problem. I had to try a lot of trial and error before I actually fixed the problem.

Initial Issue

The problem started when one day I couldn’t start my PC. I would turn ON my CPU and nothing displayed on the monitor. Here’s some of the common steps that I followed.

  • Opened my cabinet and took out the RAM and turned ON the CPU. The motherboard made a BEEP sound which concluded that the motherboard was OK.
  • The next thing that I did was take out the TP-Link PCI Wireless Lan Card that I had installed few weeks back. To my surprise, the CPU started loading again but it got hung up at the Windows 7 startup screen.
  • The next thing that I did was run a dignostic of system memory. Sometimes a few bad blocks in memory causes issues. The diagnostics (Dell) included everything from memory scan to HDD scan. Everything was good.
  • I tried to open Windows in Safe Mode but it got stuck at CLASSPNP.SYS. At least now I was sure that there was a driver issue, not a hardware one.
  • After the safe mode didn’t work, I tried to open it in “Last Configuration that worked” mode. You get these options after holding down F8 before Windows boots. Sadly, that didn’t work either.
  • The next thing was to insert my Windows 7 DVD and try a startup repair. However, the repair was not able to solve the problem.
  • The next thing that I tried was using the old PSU to see if the new PSU was a problem. That didn’t work either. Both the PSUs are fine.
  • My final step was to reset the BIOS. Sadly, that didn’t solve the problem either.
  • At some point of time, it came to me, that the problem must be with the onboard ethernet driver. Since it was removing the Wireless Card that enabled the CPU to load again. So, I went back to the BIOS settings and disabled the onboard etherner driver. Then I restarted the PC and to my delight, the Windows 7 loaded.

windows 7

New Issues

Once I had managed to load Windows 7, my first priority was to enable networking again. Since I had disabled it from BIOS, I had to find a different method of networking. I took a look at the System Information of Network Adapters and old drivers were still showing up. So, basically I had to remove them from the Registry as well. To know about how you can remove adapters from the Windows Registry, go to this link.

windows 7

The next thing that I tried was contacting tech support of Bitdefender. I had contacted them in the past when having PC problems. Generally, they are good at giving you ideas which you might have missed. They suggested to me that I use a USB adapter, since the motherboard driver was disabled.

Luckily, I had an extra USB Wired LAN. I installed it and my networking was running again.

windows 7

I finally had access to the Internet.

System Checking

After everything seemed to work properly, I did some thorough checkup of my system.

  • The first thing that I did was Disk Checking. It’s particularly helpful when there are disk errors. It also removes bad sectors and fix file systems if there are problems.
  • The next thing was a virus scan of my system. I use Quick Heal on my system. But in exceptional cases, I also download other Anti Virus softwares and run them just to make sure. Sometimes, viruses do make unwanted changes to driver files which causes problems. Since Quick Heal didn’t find anything, I downloaded the Bitdefender antivirus software. I downloaded the Total Security one. They have a trial period. Once installed, I ran it. After the scan was complete, it did find one Trojan which I removed.
  • The next thing was deleting all the previous system restore points and creating a new one. System Restore does restore original driver configurations, In my case, however a driver caused all the trouble.

In between all this, I was impressed with Bitdefender. I still have few months left with Quick Heal before my registration expires. After that I may just go with Bitdefender.

It’s been more than 3 weeks since all the trouble and everything is still running fine as far as I’m concerned.

Please note that for each Windows user, troubleshooting varies greatly. What worked for me may not work for you.


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Lahaul Seth

Software Engineer, Open Source Enthusiast & Blogger - I also own Lion Blogger Tech which focuses on Open Source, UI, UX, Technology.

I also own Open Source Software News which is a curation site for Open Source Technology News & Updates.

Also check out my personal site.