in addition, you could try this
http://security.symantec.com/nbrt/npe.aspx
or
http://www.microsoft.com/security/pc-se ... moval.aspx
it will perhaps get rid of whatever is changing the settings, but probably leave it up to you to restore them.
next time, use a decent browser and keep Flash & Java up to date, block JavaScript and use common sense and things like this won't happen, no matter how much porn you browse (I would know).
I haven't used an AV in years, but I always turn off my monitor and type my password right-to-left when entering my bank credentials, just in case.