Detele "C:\Users\YourName\AppData\Roaming\VEGAS\FX Packages" and "C:\Users\YourName\Documents\OFX Presets" and "HKEY_CURRENT_USER\SOFTWARE\DirectShow\Presets\FX Packages"
Uninstall with a third-party uninstaller like Revo Uninstall using the advanced scan mode, which can remove left-over registry entries and other pertinent data files the OS uninstall leaves behind (which in usually the root of recurring issues). Revo Uninstall has pro and freeware versions. The free version is usually adequate unless a forced uninstall is needed, which is in the pro version.