There are (at least) 5 female singers and one band using the stage name 'Michelle' -
(1) Michelle (*February 15, 1972 in Villingen-Schwenningen) is the stage name of German singer Tanja Shitawey (née Hewer) who represented Germany in the ESC 2001 with "Wer Liebe lebt" ("To Live for Love").
(2) Michelle McManus from the UK was the UK Pop Idol winner in 2003 and is best known for "All This Time", just credited 'Michelle' on her releases.
(3) Dutch singer Michelle Courtens participated at the ESC 2001, she did perform "Out on my own" to place 18.
(4) Michelle Narine from Trinidad released the track "Standing Here All Alone" in 1996 in the UK.
(5) Norwegian singer Michelle Purvis did perform "Baby don't stop the music" in the Norwegian selection to ESC 2008.
(6) A four piece band from Spain that formed in 2000. They released their first full length album in 2007, titled Rock 'n' Roll Babilonia