I recently performed a MySQL upgrade on Windows Server 2008R2.
I moved, moving from MySQL 5.1 to MySQL 5.6.22 (Community Edition).
(NOTE: PHP The server is currently using PHP 5.3.0).
To address concerns about the broad nature of the question, this is the specific Windows Event Logevent log message:
Faulting application name: php-cgi.exe, version: 5.3.0.0, time stamp: 0x4a492a25
Faulting module name: php5ts.dll, version: 5.3.0.0, time stamp: 0x4a4929bb
Exception code: 0xc0000005
Fault offset: 0x0015e1b0
Faulting process id: 0x7bb4
Faulting application start time: 0x01d01fa8dec6e9a6
Faulting application path: C:\PHP\php-cgi.exe
Faulting module path: C:\PHP\php5ts.dll
Report Id: 2e661541-8b9c-11e4-a303-001b210e0a6a
Faulting application name: php-cgi.exe, version: 5.3.0.0, time stamp: 0x4a492a25
Faulting module name: php5ts.dll, version: 5.3.0.0, time stamp: 0x4a4929bb
Exception code: 0xc0000005
Fault offset: 0x0015e1b0
Faulting process id: 0x7bb4
Faulting application start time: 0x01d01fa8dec6e9a6
Faulting application path: C:\PHP\php-cgi.exe
Faulting module path: C:\PHP\php5ts.dll
Report Id: 2e661541-8b9c-11e4-a303-001b210e0a6a
The one difference that stands out, is that Drupal uses PDO for access, and I'm wondering if there is a potential issue there (re: versions ...with the version being used, since all these sites worked fine underwith MySQL 5.1).