I think the lesson here is don't take anything at face value or rather don't just click delete without checking what will be deleted.
However, in this case most people wouldn't know that actskin4.ocx was used for the skins in avast or other programs using skins.
I usually run scans directly after any update, that way if there is an influx of detections then it is possible that they may be false positives so require further investigation.