Browse vmdk file in Windows

The only way you could know for sure would be to run an equivalent test like memtest86 but for hard disks. I don't know if anything like this exists, because it would of course wipe all the data that is on the disk.

Reading corrupted data is a known problem with disks though - generally they're pretty reliable, but filesystems like ZFS include checks to make sure any read errors don't go undetected as they do happen.

Have you re-run memtest86 since the problem happened? Two crashes on their own are pretty ordinary, especially running non-trivial things like a VM under Windows. Hardware also does deteriorate over time, and it could have even been something as simple as a brownout that didn't cause your power supply to shut off - assuming you're not connected to a high quality UPS.

I'm also not sure what you mean by SSDs being more 'stable' - they are widely known to have a significantly shorter lifespan than hard disks - people choose them for speed, not reliability. Even Intel said at the last Linux Australia conference they wouldn't use SSDs for mission-critical data just yet (that was a very interesting talk, go watch the video if you weren't there!)

Disabling the vmware service will stop it, because you are disabling the communication between the guest and the host. The sleep signal sent from the OS (which is where it originates) is translated through vmware tools, to a pause command. Stopping the service will also compromise all the features of vmware tools like freeing up the memory and other important aspects of running the vm in vmware and performance of the host will suffer.

To solve your problem, go to power settings in windows (right click desktop > personalise > screen saver > power management) and change when your computer goes to sleep. that is all is happening, the default settings for windows 7 is to sleep after 30 mins. This is being sent to the host via vmware tools, which is why disabling the service worked. but that is a real bodge, just change it to 'never' sleep/always on.