Maintance for an external hard drive

I have been following your recommendations and doing maintenance on my computer on a regular basis. Today, I had a song go missing from my ITunes music files that are stored on a Maxtor external drive. The weird thing is the artist and album folders were there but the contents were 6 photos and I think some files from a game. (They opened up to a preview screen and showed animated women's clothing)

Anyway, this got me thinking that perhaps I should be doing maintenance on my hard drive to keep it free from malware and running tip top. If this is the case can you recommend some tools to do maintenance. Thanks.