I get a blue screen on my Dell 1420 laptop with Vista SP2 when installing. It happens at different points of installation. I have tried several times but it keeps happening. I have to go to saf mode to uninstall.
I did not have a previous version of Avast.
First download and run free Mbam, to check if your system is clean. http://www.malwarebytes.org/mbam.php
Be sure your prior AV is completely removed. (You could need a utility for that)
Here’s the one for avast: http://www.avast.com/uninstall-utility
Run this in safe mode before you try another clean install.
asyn