prolific warnings

[REDACTED]

Why does Avast keep telling me it has just blocked something dangerous three or four times per night when the computer is  doing nothing, is it inventing problems to make me think it is doing its job?
I have run avast,superantispyware,malwarebytes and all say all clear

[Lisandro]

Can you post a screenshot of the warning?
Is it a webpage or an infected file being warned?

[REDACTED]

This is a photo of a screen print of one of them, it keeps doing it all night, don't know what the others said, it has only just started doing this recently
Also I have to keep requesting many captcha images as I cant read them. Oops after the fifth go I realize they seem similar
http://tinypic.com/r/34f07qw/8

[mchain]

Why does Avast keep telling me it has just blocked something dangerous three or four times per night when the computer is  doing nothing, is it inventing problems to make me think it is doing its job?
I have run avast,superantispyware,malwarebytes and all say all clear

Behavior such as this is often a key sign of an unknown malware infection.  Here, you've got avast! (your a/v) blocking ?? something.  This is especially true when you do not have any browser(s) open.

Could you attach a screenshot of the avast! block?  You can capture the last block screen by using Snipping Tool (Win 7 and Win 8.0 or 8.1) by right-clicking avast! icon in system tray and clicking 'Show last popup message' (lower right corner of desktop) and attaching it in your next reply.  Otherwise, Alt+PrintScreen should work, then paste to Paint and attach.