After the vista update last night Defender has appeared in the notification area of my toolbar with a yellow triangle and an exclamation point. when I click on it to resolve what ever the issue is it tells me that defender needs to be updated, also in checking the Security center, if also indicates that defender is out of date. when I try to as it to update or look for an update I am told that it is up to date however nothing changes. I still have the defender notification on my tool bar, and the security center still tells me that it is out of date.
any ideas how to deal with this?
any ideas how to deal with this?

Nothing came up. Have been playing around with PC to see what happens. Tried to install "One Care" to see if this would produce anything. Two things of note. Something is informing me that mt PC is infected and trying to force me to download a program called "Wingard" (or similar - I close it down before it can get a hold) and I am getting another error message telling me that "c:\windows\system32\drivers\fidbox.dat is corrupt and unreadable. Please run chkdsk utility" - This is in ref to the OC setup.
Do you have a terabyte HDD or something?