On Access Scanner failed to start

I just downloaded the antivius software and when I restarted the computer and the program started it told me that the on access scanner failed to start. I clicked the turn on button and the error continues to come up. What can I do to fix this. I am using Microsoft Vista (64). Thanks for your help!

do you have any other security apps running. you could boot to safe mode and see if it works. if it does, then another program is conflicting with it.

the event viewer sometimes gives some info.

I uninstalled the other firewall/antivius software that was on the computer. All that is on the computer is the Microsoft Security Center.