After logging in to my computer, the screen goes black with only the cursor showing. I am able to start the task manager, and start the command prompt. I can then start explorer.exe and load windows as normal. I tried two system restores to different points, both of which failed. I have tried to run avast! which results in the following error: "Unable to start scan. There are no more endpoints available from the endpoint mapper." I have also run dkschk /f /r before restarting, and the problem continues. Any help would be greatly appreciated!