Problems in booting up

Hi, to be honest my computer probably has a serious problem. When I try to start up Windows normally, I type in my password for the user account and then it just freezes, it doesn't load. So I think, okay, I'll just try to start up it in Safe Mode, no problem. But when I try to start it in Safe Mode the computer freezes at classpnp.sys and doesn't continue. I'm at a loss about what to do (not that computer savvy, so plain terminology please)

My computer is a Gateway Desktop, running Windows 7 Home Premium (64bit), intel premium processor, 1 TB hard drive, 6 GB DDR3 memory.

I tried using the "Last Known Good Config" option, to no avail. I got the "Replacing invalid security ID" message. I let that go for about an hour when I stopped it, as it was going nowhere.

If it makes any difference, I have also installed another operating system (Ubuntu).

Joe S

Excellent Member
Maybe that Ubuntu install corrupted something in Windows startup. Did you try startup repair or sfc /scannow ?

No, I'm running Startup Repair now.

I ran Startup repair. When it finished, I restarted my computer. All I see is a black screen with my mouse cursor. I've been kinda patient and waited with it for about 10 minutes.

Also, when I tried running Ubuntu, it gave a message saying to run "chkdsk /f". Before I do things I know next to nothing about (all I know about CHKDSK is that it's short for 'check disk'), I decided to ask for opinions here.


Excellent Member
Microsoft Community Contributor
Startup Repair will fix several problems, but there are some it does not seem to be able to fix. Can you boot into anything that has a command prompt, like the WinRE environment using F8 or booting to a Recovery CD or Install DVD?

When does the black screen occur, before or after the Windows Logo?

Hard to say what Ubuntu might have done to your system. It normally overwrites the MBR and removes the Windows 7 boot files, but it seems that did not happen in this case.

You might want to download and burn a Partition management software to look at your hard drive. Partition Wizard or G-Parted will usually work, and G-Parted may be on the Ubuntu DVD if you just load it for trial and not install it.

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