I made a bad mistake following someone advice on the problem unable to detect external drive. I have a buffalo external drive which I cannot detect for months even though the external drive is spinning (I can feel the vibration) and there is a a slight led lighting but not as bright as it used to be. So after searching for solution on the internet, I found one that requires two changes in the registry.

The changes I made was to delete the upperfilters and the lowerfilters of the registry below:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E967- E325-11CE-BFC1-08002BE10318} 

After I made these changes, my windows 8.1 starts up with error and I have tried with start up with safe mode, restore, etc. but it just continue to start up with error with options to restart or shut down. I did not back up the registry. When I say it starts up with error, it means windows did not complete the start up so I can't get in to change the registry back. Please help.

• Edited by kwng Saturday, April 04, 2015 6:20 PM

I am still looking for another Windows PC 8.1. In the meantime, there is an option to start the windows as command prompt and I managed to launch the regedit . However, upon checking the value upperfilters is still EhStorClass and the value  lowerfiilters is still PartMgr even though I have deleted them earlier that caused this problem. However, I still unable to start up Windows.