That's strange in that it isn't possible to tell the home version to ignore an actual virus. Are you sure it wasn't a 'Potentially Unwanted Program' a.k.a. a PUP?
Double-click the taskbar icon to open SecurityCenter
Click Navigation at the top right corner.
Click Quarantined and Trusted Items in the list below
See if it's in any of those 'drawers' - click them to expand.
If not then maybe you turned off a detection setting
Go back to Navigation by re-clicking it
Scroll down to Real Time Scanning snd click it
Make sure it's on and that the appropriate boxes underneath are checked.
In the Navigation menu you can also get the History and Logs from the left column.
Right click on your shield and choose navigation, then quarantined and trusted items.
You can also check in History and Logs for detected threats.
Sorry Peter, I must have been typing while you were posting!
No problem Ron. Two are usually better than one here...LOL