I've just started having this during the last week.
On startup, my dell dimension pc runs into a frozen state while doing or after doing the virus checks, before entering windows.
On restarting it enters 'SAFE' mode and then runs windows.the settings all change to SAFE mode with low resolution and colour settings.
BUT when windows runs after another restart, the screen settings remain in safe mode, without the words SAFE mode appearing on the desktop.
I tried to change them back to my normal ones...
It told me restart before they take effect.
I did so, but alas no change in settings.
Is it a virus? Hopefully so because the pc is just over 10 months old!!!
Well many thanks for any replies, and hopefully nobody else is suffering with this too.