it's worth trying the security tools at portableapps.com
you can run them from about anywhere. flashdrive, cd, or a spot on your windows desktop
my searches always get redirected
try one of the browsers from portableapps. see if searches get redirected.
also, if you do decide to wipe everything and start over, take the
time to make a second partition on your hardrive. very handy for storing data while messing with operating systems.
also, make and use a limited windows account for surfing. that way if it gets messed up you can use the admin account to delete the messed-up account and make a new limited acount for surfing.