A bit of common sense goes a long way here. Files that are less than 2 MB (2,000 KB) are most likely going to be rubbish. There's a high chance they will be autogenerated results replicating the name of the file your search was, & most of these are pc viruses. So why search for zip files or downld zip files?

oldmac you need to learn what mac files are & what type of icons they have, etc. Some text files are intended for pc.