I was small and I was brown…
I was lying on the ground…
Like a Rock!
I always thought that was an awful theme song for something that was useful only when it was moving something an awful lot like rocks. But, when you apply it to a laxative, things start to make much more sense.
Any song by the Cars.
Back in high school, I had a crush on this cute girl, who of course only liked me “as a friend.” She was a huge Cars fan. When they came to town she went to the concert, and Monday morning at school she bragged about getting backstage and giving a blow job to one of the band members (don’t recall which one). She was either 16 or 17 at the time.
She may have made it all up, but I actually don’t think she did. Either way, that was enough to put me off the Cars forever.
As far as I’m concerned, in this post “ruined” means “made awesome.” I do remember of the Wayne’s World scene every time I hear Bohemian Rhapsody, but I think that improves the song.
“1812 Overture” and that breakfast cereal commercial of the 1970s (Quaker Oats). "This is the cereal that is shot from guns…
Part of Beethoven’s 9th symphony were used in the closing credits of the “Huntley-Brinkley News Report”
William Shatner’s covering of “Mr Tambourine Man”.
“Don’t Stop” was one of the few non-Stevie Nicks songs I ever liked by Fleetwood Mac. Bill Clinton using it to kick off his inauguration ball trashed it for me forever.
What about *Come Sail Away *and *Heat of the Moment *being associated with Eric Cartman and South Park?
It’s not so much “ruined”, but it now makes me want to sob: “You Are My Sunshine”, because of the scene in Silverlake Life: The View from Here, a documentary about a filmmaker and his partner living and dying with AIDS. When Tom sings it to Mark… oy.
Because of one of my favorite movies of all time (The Conversation), “When The Red, Red Robin Comes Bob, Bob, Bobbin’ Along” will always have a sinister edge to it to me.
If you had never seen the movie, you might find Mike Oldfield’s “Tubular Bells” to be a pretty cool (albeit long, and epic) song. But it is SO associated with the movie “The Exorcist”, most of the people of my generation can’t even handle a few bars without demanding that it be turned off !
Just thought of a new one: all banjo intros have forever been ruined by Deliverance.
Yep, if I’m in the car and that song comes on I’ll even do the headbanging.
I can’t listen to “Angel” by Sarah McLachlan without thinking of those SPCA public-service announcements with the poor little dogs in the shelters. 
Also, “The Scientist” by Coldplay was ruined for me one day when I was idly going through the cable stations and saw a show in which a couple was standing in a train station, crying, while this song played in the background. I didn’t see the rest of the show, just that part, but I now associate “The Scientist” with inexplicable sadness and grief.
I forever associate this with Geraldo Rivera and “Willowbrook”.
For years in the 80’s, The Temptations’ Heard It Through The Grapevine was ruined for me by those stupid anthropomorphic dancing raisins. Only in the last few years is it regaining its status as an awesome Motown classic again.
I can’t hear James Brown’s “I Feel Good” without thinking of pooping.
Journey’s Don’t Stop Believin’ and The Sopranos finale.
Kid Rock’s Bawitdaba and The Shield pilot episode.
Daisy and 2001: A Space Oddysey.
Viva Las Vegas and Viagra.
Not ruined, in fact enhanced, but I can’t hear Breathe Me by Sia without remembering the Six Feet Under finale.
Wait - I misread the OP. My examples are what I believe to be fantastic uses of those songs - it’s just that they’re ruined as songs for me now b/c I can’t help think of the scene where they were used.
Second movement, to be precise.
I have a Mike bootleg CD which has a radio interview. Mike says that some kids were scared of him, and that it’s not devil music. I also read somewhere that he eventually watched “The Exorcist” and laughed his head off.
For me, Mercedes Benz actually used Janis Joplin’s Mercedes Benz in an ad, and some company, a car company I think, used the Who’s “Can’t Get Fooled Again” which seems particularly clueless.
Whenever I hear Tom Petty’s American Girl, I think of serial killers all because of The Silence of the Lambs. It’s the song the senator’s daughter is singing in her car when she runs into Buffalo Bill.