tedster - 3:13 am on Nov 23, 2008 (gmt 0)

Well, Google has made it clear that they might "reset" all their measures of a domain when ownership changes, so it's worth asking. A total reset usually doesn't happen if there are no content changes, however, since it's common for entire businesses to change owners. In addition there certainly have been cases where previous owners knew how to sabotage a site after they sold it.

It's also possible that your new server allowed a hack to occur. I'd really check that angle out of the other ideas here aren't connecting. Some of the hacks around today are pretty sneaky, cloaking links so that only googlebot sees them, for instance. It's a common reason for all ranking to vanish.