I don't know if this is an inherent vista problem, or whether it's due to defender, but many of my settings seem to be wiped each time I log off.

Recent examples:
1) I have IE set to use a proxy, yet on each restart, not only is it not set to use a proxy, but the proxy details no longer exist (and yet they work when changed without restarting)
2) I specified the DNS servers explicitly in my wireless lan connection tcp/ip properties, yet on restart, it's reset to auto DNS
There are also some startup programs which keep giving issues - one in particular which windows keeps asking me if I want to run, I keep unchecking the box marked "always ask", and yet it still keeps asking. I've had a look in the windows defender software explorer to see if I can do anything useful there, but nothing's apparent.

I had some not dissimilar problems on a winxp system with defender installed in the past, and I just had to turn defender's auto protect off, because it kept resetting stuff without asking me, so I'm not sure if that's the issue here.

Anyone else had similar problems. What can I do about it?