Compatible Freeware Anti Virus for Windows7

Hi All - I have recently installed Windows7 public beta and one of the first chores was to chase down a compatible free AV. Upon scouring the net for suggestions I found reports that all the big three free AV programs will run okay on W7. AVG and AntiVir will, apparently, run trouble free....Avast is reported to work fine but for some reason the W7 Security Center does not recognise the definition updates and continually reports them as out-of-date even though they are not. One dedicated Avast user reported this can be overcome by running the initial execute/setup file and Avast's main process in Vista compatibility mode. I have downloaded and installed AntiVir Free...so far - so good!

cheers.....JIM