Cannot log in - asking for user and pass

I cannot log into Windows as of yesterday. It used to go to a user icon screen of the 5 people I have set-up. Now it starts at a login screen where it is asking for a username and password. I had never set any passwords to login. If I type my username and enter it starts to go to my wallpaper screen and then says "closing network connections' and goes back to the login screen again. I tried using Administrator login with blank password which does not work. I ran system diagnotic test thru setup and had multiple errors.
- System memory failure MATS
error code: 2F00:0119
- MARCH A TEST
error code: 2F00:0419
- MARCH B TEST
error code: 2F00:0819
- MARCH C TEST
error code: 2F00:0719
- MARCH X TEST
error code: 2F00:0919
- MARCH Y TEST
error code: 2F00:0A19

 

I get the same login screen when using safemode.  Later today I plan on swapping out the memory but I don't feel this is the true problem.  If this is a virus, is there anyway I can log on to even run my Norton??  Anyone have any ideas of what to do next?  Thanks.