I haven't debugged in a few years, but it's "nice" to see the good old antivirus blues rear its ugly head.
0x24 almost always means antivirus and/or other security software funk, especially on known-well hardware.
1) Uninstall Tune-Up Utilities.
2) Remove Avast with tool they offer (safe mode is best). Replace with MSE to test, or on permanent basis.
3) Very much could be the cause, as noted above:
Boot to safe mode, delete the shown driver file then open Regedit. Delete the driver's key at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services
2: kd> lmvm PxHlpa64
start end module name
fffff880`014e3000 fffff880`014ee380 PxHlpa64 (deferred)
Image path: \SystemRoot\System32\Drivers\PxHlpa64.sys
Image name: PxHlpa64.sys
Timestamp: Fri Feb 02 16:24:22 2007 (45C3AC06)
Translations: 0000.04b0 0000.04e4 0409.04b0 0409.04e4
(If you're lazy and don't have Safe Mode configured, normal mode should be ok.)
Reboot to normal mode. If cd/dvd drive stops working, that's a good thing. We'll fix that next.