Shareaza

For the last month or so, each search for a video show potential downloads of only 10mb or less, most or all of which are probably malware, even for known files that I already have which can be 1gb or more. What is going on? Is there some setting I am missing?

Well, do you pass the connection test? Do you use a security filter? What networks are you using exactly (gnutella, G2, eDonkey, DC++)?

Provide screenshot please.

You could also try doing a reset on the host cache. Getting stuck on using "fake" hubs would look like this, since they'd only provide you with the same fake hits regardless of what you look for, and probably would only connect to each other so you would not have access to other hubs that could provide real hits.