Screen goes black after login

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!

I'm currently using basic directions in this thread: http://www.techspot.com/vb/topic136933.html

I'll post with results.

avast! uninstalled since it seemed to do no good, avira installed and now running. (Luke Firewalker?!?)

Problem solved with avira.