the problem is your PC Graphical Experince is poor to play the game you are installed.
my advice to look up first for your VGA Card device, is it supported by the game..? the pixel shader, minimum memory, etc..
if can afford one, buy some middle rate VGA type, that cost you not to many.. (choose any from NVIDIA brand type)
then, always to remember is checked UPDATE monthly (if it's possible from the manufacturer site) all your Device Driver component, such as :
- Sound Card
- VGA Card Driver, etc.
the last one is ALWAYS install the latest Directx Software
check this link : http://www.filehippo.com/download_directx/
and this link : http://www.microsoft.com/downloads/details.aspx?FamilyId=2DA43D38-DB71-4C1B-BC6A-9B6652CD92A3&displaylang=en
Because game developers are always using their optimum graphical experience nowadays known every day, so keep it up to date.
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well, from your additional details, looks like your PC at the end repairing level is need to clean re-installing all the Windows setup
but first yes, try to check "the fan and the connector" of your video card, whether by PCI/PCI-E or AGP, make sure that it's been run smotth and properly attached.
or if your PC has on-board/built-in Video Card on it, then use it temporary, and disable the external VGA card or take it set back to default all setting from the BIOS setup.
later change it back to it normal condition with your Video Card attached.
hope this works
Good luck