for details of this problem, please see my original post here at http://www.bleepingcomputer.com/forums/t/206488/ff-ie-intermittently-refuse-to-access-internet/
please read it carefully. thanks.
I didn't give system specs there - windows XP home, SP3, right up to date, 550mhz CPU, 120g and 40g HD's plus 500g external drive, with 100g windows partition on it. Zone alarm Pro firewall, avg8 free antivirus.
I use BOOTIT NG, a dual boot, partition manager, and imaging program.
I posted this problem at Protonic, and have had no answers there. my original post here was closed because I was considering using combofix.
so, left on my own, here is what I have done.
bootit ng does a bootable image on a weekly basis, so I decided I would go back a bit to when I knew the problem was in its first stage -browsers would quit, but closing and restarting them resolved the problem.
the image is usually copied to my 100g partition on my external HD.
so I copied my image for jan 14, to my second HD, and booted from it.
now the browsers work, and everything is fine. after using the system for a while, with no problems, AVG update comes up and says it needs the system rebooted. this doesn't normally happen with AVG, so there must be some significant program change.
immediately upon reboot, the browser problem occurred.
so I replaced the jan 14 system with the jan 7 bootable image, uninstalled avg8, and now the system has been running perfectly since that time, feb 26 or 27. the browser problem has occurred ONCE, and restarting it corrected the problem.
so now, how do I find whatever is on my 'production' system that isn't on my jan 7 system, that prevents the browsers and email from working, although there is still internect connectivity ?
googling, I read that installing KB967715 killed internet access.
so I uninstalled it, no change, so also uninstalled the related KB961118. jproblem still happens - browsers will not work, and re-booting the system has no effect.
I used Windows search to discover everything that had changed in the past week - hidden files and all. examined all that data and could see nothing suspicious.
SO - I made an image of my production system , so I can get back to it no matter what I do to it.
now I ran combofix. when it finished - I followed directions carefully - the problem still existed.
so I copied the combofix log to my E drive on the external hd, booted my 'temporary' jan 7 system, and began to check the items listed in the log, using google. to discover what each file was used for.
I could find nothing suspicious.
so now I still don't know what makes one system OK, and the other no good for internet access. (it does everything else normally)
so if I can get permission to upload the combofix file, and have someone examine it to tell me if there is something there I couldn't see,
then we can confirm whether there IS a virus or not.
if there is no virus, I would plan to copy the jan 7 system to replace the production system, and then copy the feb 26 DOCUMENTS AND SETTINGS from that night's backup, which would make the system basically current.
this will still leave the original problem of browsers stalling, which I would hope to get some help for also.
Vern de Guerre