I too, like the others can’t understand why you would want to do this even after your explanation. Surely if you want to try something out to see if you can get on with it, you don’t then hack it to bits, how can you possibly evaluate it fully? Try it for a few weeks in full and then make your decision.

If you are still hell bent on crippling a great product, you will have to disable the startup entries (untick them). windows start>run> and type msconfig and click on the Startup tag.

Untick the Avast entries, names start with ash (you wil also see the path leading to the Avast directory), you should untick them, you can go back later and tick them when you eventually come back to your sences and enable them.