nokia 5530 virus help!!!?

[James]

ok well i got my nokia 5530 xpress music for christmas this year. about 2 months later my friend showed me this app that gives you free internet. its called 'opera mini'.now iv ben using it 4 abou 2 months then yesterday my phone started acting up,not letting me enter messages r exiting out of apps by itself. now it doesnt let me do any thing atall jus a frozen scree. the reason i mentiones the app opera mini is because i was thinking that my phone might have gotten a virus. what do ido !!! plz help! im with vodafone