Here you can watch Britney's performances at MTV Awards all those years ! 

...Baby One More Time (1999)

Satisfaction/Oops!... I Did It Again (2000)

I'm A Slave 4 U (2001)

Madonna,Britney Spears,Christina Aguilera - Like A Virgin/Hollywood (2003)

Toxic (2004)

Gimme More (2007)