Where a defendant who previously served a term of imprisonment for murder could not argue that a person in his position would be unaware of his status as a felon when challenging his conviction for illegal possession of a firearm.The 7th U.S. Circuit Court of Appeals affirmed a decision by U.S. District Judge Virginia M. Kendall.In 1998, an Illinois state court convicted Charles Williams, then a teenager, of first-degree murder and sentenced him to 30 years in prison. Williams was paroled in 2008, but had his parole …