spacesurfer

The OS data is not stored on a partition but is stored on a VHD. Your other data can be stored anywhere, another partition or another drive.

you simply tab

You need to REPURPOSE the New command buttons. Search on this. You'll have to assign the repurposed macro to the ribbon by customizing the ribbon. See pinned topic on how to modify the ribbon by me. Can't help much more than that since I haven't had a need to repurpose commands but I believe that's what you're looking for and can be found by googling!

I think XP doesn't have drivers to recognize VHD hard drive at boot. It can after it has booted.

Which drive letter are you trying to mount to? Perhaps there is a conflict with the drive letter assignment. I always change my virtual drive letter to "V" for virtual with UltraISO. I use a "portable" UltraISO (I installed it in VM and copied all files from Program Files folder to another location and it works without having to install. The virtual drive mounting also works without install. It just requires to be run as administrator. Are you running UltraISO as admin?

Use ccleaner to clean your computer and also check the startup apps in ccleaner and disable those that can be.

I use InfraRecorder. I believe, right now, it's the only one available as a native 64-bit app (they also have a 32-bit). And it's portable. No need to install. And yes, it's FREE.