If you start experiencing STOP errors after a recent Windows Update and are running AVG Anti-Rootkit or spyware, KB938371 may be the cause of your troubles. This update, a patch for the Windows Trusted Installer, has reportedly caused error 0x0000007E in avgarkt.sys and 0x000000D1 after uninstallation of Anti-Rootkit if Anti-Spyware is left in place. It can apparently cause a cascading failure through these particular products and possibly AVG's Antivirus as well. It also happens to be a prerequisite to installing Service Pack 1 RC1 for Vista.