Black screen and lsass.exe-application error (0xc0000005)

My computer has stopped working. (Systemax Ascent A20 running windows XP installed from factory) When I turn it on I now have a black screen and a windows box lsass.exe-apllication error. In the box it states " the application failed to initialize properly (0xc0000005), Click on OK to terminate the application." Clicking on this box only eliminates the error box and then I just have a black screen and my cursor. This happens in both normal and safe modes. I can not use the computer at all. I'm currently using a friends notebook and searching for help.

Please visit this webpage for a tutorial on downloading and running ComboFix:

http://www.bleepingcomputer.com/combofix/how-to-use-combofix

See the area: Using ComboFix, and when done, post the log back here.