Laptop Freezes when entering WIndows7 if power cable is left connected

Toshiba Satellite P745

Windows 7 Home and Ultimate (same happens with both versions).

My laptop ALWAYS hangs (just before entering windows, on the 'welcome screen') if it is plugged into the AC-Power.

BUT:

if I disconnect the power cable and battery then plug it back in, then its fine.

but the second I switch off or restart or sleep my computer, then it will Hang or Freeze again the next time I switch it back on. (unless I unplug the power cable and plug it back in again) !

This happens every time, regardless if I use the battery or power-pack or both.

I have no idea what is causing this.

i need to unplug and reconnect the power every time.. (otherwise it will hang).

if it hangs, then i need to do a Hard Switch off.. and it ruins my software registrations..

many apps and software need reinstalling every time when I do the hard power off.

I have got a new hard drive; reinstalled windows; bought a new battery and AC-Power Pack.

i have no idea what is causing this.

but the electricity supply to the laptop needs to be stopped or broken or unplugged so that it can start again successfully.

is there any Windows Start-Up log i can view or install to see EXACTLY what part of the start-up process my computer hangs ? coz this might help me find the problem.

- I tried disabling the AC-Adapter and ACPI battery (in the "Device Manager") but this did not help.

- Please let me know if you have any ideas for me.

Thank you