Thanks guys for all your suggestions, I've installed Bitdefender and hope it does the job - read a lot on Google Play re: ransomware it seems quite common and there aren't many good antiviruses out there to stop it. I installed Kaspersky, then removed it which messed-up my proxy settings, I could not connect to my wifi hub etc., had to reset the entire phone; so anyone thinking of using Kaspersky don''t install it as a trial it messes-up a lot of stuff.