virgofluff874 Please post the full lastexception here. You can attach it to your reply if you delete the first line of text in the file. Or you can copy the text and paste it into your reply.
And I'd like to know whether this error is showing up when or just before the game crashes, or it's happening before and the game crashes later. Some exceptions don't trigger a crash on their own.
Please also provide a dxdiag. Click Windows key-R, enter dxdiag in the run box, wait for the scan to finish, click "Save all information," and save the file to your desktop. From there, you can attach it to a reply using the paper clip (Attachment) icon included with the other formatting buttons.