Knocked down by cancer, Sheryl Crow is back to rock 'n' rolling.

The 44-year-old singer made her first public performance Tuesday after undergoing breast cancer surgery in February and subsequent radiation treatment.

Crow was hired to sing three songs at a sales presentation to advertisers by My Network TV, a new broadcast network launching in September that will use her song "A Change Would Do You Good" as the theme to one of its series.

She played guitar and smiled, but appeared to move gingerly onstage. Showing rustiness, she stopped the song "Soak Up the Sun" and started again after flubbing the lyrics.

"The words are just coming back to me now," she said. "I knew it last night. I think the radiation went to my brain."

Like the lyrics suggest, she seemed to have fun while ending her brief set with "All I Wanna Do."

"This is the first time I've played in ages," she said. "I'm just happy to be here."