Just in case anyone else gets this issue, its NOT hardware. Firefox related.
Memory leak caused by Firefox 3.5 being left open.
1) Start firefox
2) Walk away from PC (or don't use Firefox) for 15 - 20 minutes
3) Right click on recycle bin or use Windows Explorer and right click on a folder or file
4) Explorer.exe faulting exception
I can re-produce on a bare Windows Vista 64 bit install (no SP or antivirus, no office no utilities, just OS + Firefox).
I've used two separate motherboards, two separate hard disk drives, different RAM modules and two different graphics cards. The error is still repeatable for me under these circumstances.
Issue not seen when using Chrome or IE8 as default browser (6 weeks without an issue).
Just posting back about the outcome
