BSOD every time I enter Unity Mode

Question

SUMMARY OF PROBLEM
My Windows Vista guest VM has started blue-screening every time I enter Unity Mode. (The host system continues running normally.)
I'm running Vista Business (32-bit) inside WMware Player v7.1.0 build-2496824 with 2 GB of RAM.
The host system is Windows 7 Professional (64-bit 6.1.7601) SP1 with 12 GB of RAM.
The guest system has just a handful of small applications installed.
The blue screens occur even with no applications running on the guest.
NOTES
(1) I've been using the VM frequently for several weeks now without any major issues, and I've tried Unity Mode a few times before with success.
However I've mostly just been running my VM in a normal window (whatever you call 'non unity mode'!)
(2) I vaguely recall that one of the times I entered Unity Mode, many weeks ago, my host system made a bit of a drama... I think the Desktop Window Manager crashed and possibly Aero stopped working on the host OS. At the time, I guessed it was an issue with the host's graphics driver. (I've subsequently updated the host's graphics driver, and the problem has not reoccurred, which of course may or may not be pure coincidence.) But Unity Mode definitely worked, and has worked for a good length of time between my last host driver update and today, when the first BSOD occurred.
(3) Prior to today, the only issue I have noticed with the VM is sometimes there is mouse pointer corruption after doing 'stuff' in the VM window (perhaps after performing actions that cause the guest's mouse pointer to change?) then moving the pointer outside the VM window: now, instead of just a regular white arrow, there's a varying pattern of pixels in two horizontal lines, a good few pixels below the bottom of the arrow. This corruption typically vanishes when I move the pointer back inside the VM window area, but often reappears (sometimes changing to a different pattern of corruption) when I move it outside again, and so on. After a varying number of repetitions (outside VMware window / inside / outside...) the corruption vanishes for the time being. (By the way, the corruption survives pointer changes on the host. So for example, I can move the corrupted pointer to a window edge on the host, causing the pointer to change to a double-arrow like usual, but the corruption is still there below the pointer.)
I've always felt the dodgy mouse pointer was a mild cause for concern! Nothing like this occurs until I start running my VM.
(4) It's only in the last ~24 hours that I've been getting the BSODs when entering Unity Mode.
This roughly correlates with Vista demanding activation (which I have now finally got round to doing!) - this may or may not be pure coincidence.
The Vista guest definitely seemed to be on the brink of refusing to work - today it kept changing my desktop wallpaper to a plain black background and saying this was my last day to activate. This behaviour stopped as soon as I successfully activated it.
The Unity Mode BSODs have occurred both before AND after activation.
(5) I have looked through recent Windows updates on both the host and the guest.
On the guest, there's nothing there other than Definitions Updates for Microsoft Security Essentials in the last month.
On the host, it's been six days since an OS update (since then, just MSE definition updates).
(6) [Update] I've tried disabling Aero on the guest. The VM still BSODs on entering Unity Mode.
The blue screen itself:
A problem has been detected and Windows has been shut down to prevent damage to your computer.
PFN_SHARE_COUNT
Technical information:
*** STOP: 0x0000001B (0x00000000, 0x00000000, 0x00000000, 0x00000000)
Log files:
WERAC16.tmp.version.txt
Windows NT  Version 6.0 Build: 6002 Service Pack 2
Product (0x6): Windows Vista (TM) Business
Edition: Business
BuildString: 6002.19327.x86fre.vistasp2_gdr.150225-1506
Flavor: Multiprocessor Free
Architecture: X86
LCID: 1033
Mini041115-01.dmp
I've run dumpchk on the minidump file. It says:
Probably caused by : vm3dmp.sys ( vm3dmp+17c6f )
I have attached a photo showing the intermittent mouse pointer corruption issue.
I've also attached a screen shot of the BSOD.
Please let me know if there's any other info I should include. Thanks in advance for any suggestions!

Answer 1

Update:
My Vista VM still blue-screens 100% of the time when I try to enter Unity Mode.
I've tried:
* Uninstalling & reinstalling VMware Tools on the guest.
* Disabling all non-essential hardware.
* Performing a disk check within the guest (no errors).
* Ensuring I have all the latest Windows updates.
* Allocating more RAM to the VM.
* Disabling graphics acceleration.
* Reducing the number of CPU cores allocated from 2 to 1.
(None of these makes any difference. Obviously I'm clutching at straws with some of these things.)
The VM never BSODs under any other circumstances. It's solely when I click Unity Mode. Help!