Prevention is far easier than removal. Follow these golden rules:

Do not use an Administrator account for daily browsing. A standard user account cannot install system-wide browser hijackers without a password.

Instead of karma only affecting the final cutscene, this feature would introduce mid-mission environmental changes social consequences based on your previous decisions. Social Reputation Meter

Removing manually can be tricky because it hides in multiple locations: browser extensions, system files, and scheduled tasks. Follow this chronological guide.