Are these the BSoD you're getting after enabling verifier?
Doesn't look like verifier is enabled yet, please enable it.
BugCheck 50 = PAGE_FAULT_IN_NONPAGED_AREA (50) =
Usual causes: Defective hardware (particularly memory - but not just RAM), Faulty system
service, Antivirus, Device
driver, NTFS corruption, BIOS.
BSOD Index
BugCheck 3B = SYSTEM_SERVICE_EXCEPTION (3b) =
Usual causes: System service, Device driver, graphics driver, memory.
BSOD Index Problematic software: Code:
Start Menu\Programs\AVG Public:Start Menu\Programs\AVG Public
Please uninstall AVG Antivirus while we are troubleshooting with your comp.
Download and install MSE and run a full scan once updated.
Microsoft Security Essentials - Free Antivirus for Windows
*Run the system file checker for repairing any damaged files within windows:
SFC /SCANNOW Command - System File Checker
*To make sure your hard drive is good, run:
Disk Check
*Run the short and long tests with SeaTools:
SeaTools for Windows
SeaTools for DOS
* Run Memory test for 8 passes preferably overnight.
RAM - Test with Memtest86+
Post back results