I bumped a slightly older thread earlier where it supposedly doesn't work because it starts momentarily and then continues to login screenm the reason I bumped was because at first the problem was reported with win7, as a new OS I imagined there would be issues with it and that others would think along the same line, yet I had the same issue on win XP SP3 which I felt had to be mentioned to make sure it wasn't an OS exclusive issue, having read Nergal's explanation, I think he is correct, as it would make sence since the whole idea of boot time programmes is to bypass protection that would be there when the whole OS has properly booted, so it can target the protected files that normally would be inaccesible, this would also make sence as defraggler before I made it do a proper defrag (which I did after a boot time) shows my pagefiles in 2 seperate chunks rather than scattered all over, and my MFT is altogethor on the top row of the diagram.
In the end Nergal may be incorrect, but I'm just saying his explanation makes logical sence to me.