I have a Win XP SP2 machine which started with the following behaviour, I believe after doing an automatic upgrade of Avast to version 5.0.677:
Just before getting to Windows welcome screen, goes to black screen with mouse pointer. Pointer can be moved by mouse but PC is otherwise unresponsive and has to be reset.
It doesn’t always do this, maybe 1 in 5 times, but when it does it usually does it twice in succession, then boots properly at the 3rd attempt.
I switched on boot logging and I have found by comparing records for good and bad boots in ntbtlog.txt that the system is crashing at the file aswFsBlk.sys.
A similar situation is reported here:
https://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=229&nav=0,62
but I have never had this Asus software installed.
Any ideas?