Yes, on my desktop PC I use Avast Anti Virus, they advertise Avast for Android. So I installed it. However, like all the other protection ware that I've seen, it transpires that when they say Android they mean an Android phone.
I thought I could perhaps still use Avast and just ignore the bits of their programme that refer to a phone. Sadly, this doesn't seem possible. As I haven't been able to by-pass the screen that asks for my 4-6 digit PIN number. Naturally I haven't got a pin number.
I've not heard of 'Lookout' my Android is a Chronus 10.1, thanks for that, I'll check it out.
I turned the tablet off and on again and Avast was gone. I've now downloaded and installed it again. It just did a scan and found no problems, that's good news. Everything seems to be fine now, no more PIN nag screen. I think first time around I must have click a PIN set button or something.