Windows 8.1 guest hangs at boot using all resources

[traflol]

I'm having some issues with my Win 8.1 VM. It used to work perfectly, but stopped working a few days ago. It might have been after updating Virtualbox,
but I can't really remember. What happens is that the machine starts to boot and I get to the loading screen with the spinning dots. Pretty much instantly after launching the
VM, it uses all the CPU and memory allocated. I have a Win Server 2003 and Debian VM that is not affected by this problem.

I left the machine booting over night and observed that it would eventually reach the login screen, however the cpu and memory
usage was still maxed out rendering it unusable. I have tried playing around with the settings, but nothing seems to work. I have tried searching the forums for this, but
everyone seems to have some other variation of the problem.

The host is running Kubuntu 14.04 LTS 64 bit.

Let me know if I can provide any other information.

[mpack]

Well, you have a dual core host and are assigning both cores to the VM, which would explain why the host is unusable when the VM locks up.

As to the lockup, I'm not sure it's a VirtualBox problem. It sounds like some kind of guest calamity to me. Do you have a backup from when it worked?

[traflol]

The host is not unusable, it is only the guest.

I do not have a backup unfortunately, which sucks because it will take some time to set things up again.

Is there no way to fix this?

[mpack]

As I said, it seems to me that this is a guest problem. There is no VirtualBox problem to fix, and I have no way of knowing what the guest problem might be. Either a bad update or perhaps disk corruption of some kind.

Does the guest boot in safe mode?

[traflol]

It does not

[mpack]

Well, you could try booting from a setup DVD and repairing the installation.

You can also attach this disk to another VM and copying off any files you need. Be very careful with this idea if snapshots (or any other kind of differencing scheme) are involved.

I see that this was originally P2V'd from a Dell OEM install. I am surprised that this ever worked, unless Dell have become more relaxed in recent years about node locking their licenses.

[traflol]

As long as you use the Dell Recovery DVD for installation it seems to work fine. I was a bit surprised as well. I could not make the installation repair work though.

The solution I'm going for is the one you mentioned; basically a fresh install and copy over the files.

After googling the issue without Virtualbox in the query, it seems that this happens with Windows 8/10 for a lot of people.

Thank you for your time!