>I am using Windows built in virus detection. As a security precaution, just in case it would fail on a specific virus, any recommendation on a small virus check utility I could use to see if it would find something Windows would not be able to?

I use Windows built-in as well but do 5 to 8 times a year a lengthy check with desinfec't, a Linux-based DVD or USB based live system which has 4 different scanning engines and does a signature update for each before checking. So, for the specific question of small (fast) check nothing from here, but thumbs up for that check totally running without dependancy of your own boot/system files, which could have been corrupted to mask infection or not booting at all.

This is offered by c't, the only good remaining IT print, but with high probability can be downloaded somewhere on heise.de, although I don't know if there are english translations of accompanying texts. Google translate should be ok...