Within a few minutes of starting up my computer, the screen will freeze and there is frantic disc activity for what seems an eternity, during which I can do no work. This is something that has only occured recently.
I have turned off all the automatic updates in the past, but I feel that another one has crept in and is going through all my programs. I use AVG so it's not a virus. How can I tell which program is causing the problem?
Maybe try safe mode. I assume you know how to get into that? When you choose to load Windows in safe mode you get a vertically scrolling list of all the files that windows is loading.
I think Windows saves a boot-log to the boot partition root directory every time it starts. Have a look there. You may need to view hidden system files in order to see it.
When one person suffers from a delusion it is called insanity. When many people suffer from a delusion it is called religion.
I have no idea how to get into safe mode. The only time I've come across it was when something went wrong and I was asked at boot time whether I wanted to boot up into safe mode.
After the BIOS finishes sending system "POST" messages to your screen rapidly press the F8 function key. Then select "Safe mode" from the text based GUI menu that appears.
It's been like this since Windows 95. I don't know about Windows 3.1, but who uses that anymore?
Download "Process Explorer" from Microsoft. Just before that activity starts, run Process Explorer and then look through the listed processes to find out which is creating and destorying file handles, or sucking up the CPU.
Another service to try disabling is "Indexing Service". It may be updating its catalog.