1. Uninstall AVG, use Microsoft Security Essentials.
2. Run System file check and Disk check.
3. Update to Service Pack One.
Microsoft Security Essentials is recommended from a strict BSOD perspective, compatibility & stability
compared to other antivirus or internet security software. It is free and lightweight:-
Do not start the free trial of Malware Bytes; remember to deselect that option when prompted.
Run the System File Checker that scans the of all protected Windows 7 system files and replaces incorrect corrupted, changed/modified, or damaged versions with the correct versions if possible: