Safe Mode is for loading only essential drivers to determine whether Windows can boot. It doesn’t load drivers necessary for other software, so AVG, or other programs aren’t initiated. Safe Mode isn’t intended for regular computing.
Log into Safe Mode, then use [Start] [Run] then key ‘msconfig’ in the window that apears and click [OK]. When msconfig boots, go to the [Startup] tab and de-select all applications that aren’t essential. Then, select the [Services] tab and do the same.
Now, reboot and let the computer boot normally into Windows. Does it now boot? If so, you can go back into msconfig while in Windows, selecting the unmarked items one at a time and rebooting after each item is selected (this will be a long process). Keep tabs on each item because if Windows fails to reboot, you’ve likely found the problem and will have to go back into Safe Mode to de-select it again.
I forget, safe mode is F8?