The fact that your system works OK in Safe Mode (w/ network) indicates that a program is running as part of your startup that is causing this condition. Safe Mode is nothing more than Windows running with a bare minimum of programs and processes necessary
to start your system (ie everything non-essential is shut off).
Solving this problem will be a hit-and-miss proposition. You will need to start your computer in Safe Mode and run a configuration manager (msconfig or autoruns) and selectively disable programs that automatically run at startup until you find the one(s)
that are causing your problem. Start by disabling non-Microsoft programs and extend that into the MS programs if necessary. These programs will generally warn you if you try to disable something that you shouldn't. After you disable some of them, you reboot
normally and see if the problem still occurs. Once you find the troubled program/process, the procedure is usually obvious on how to fix (usually un-installing then re-installing)