Need to stop SPAM emails coming to me via my website forms (three forms on site)

I have three "forms" on my website. They are html pages with the associated PHP action processing script (.php files). Anyway, all was well until I started getting daily spams, one for each form. Not a bid deal - just deleted them. Then about a month ago I woke up to hundreds of spam emails coming in by the second. All from the same email address (e.g. <1@[login to view URL]>) that changed slightly each time. My web host iPower suspended my site until I fixed the problem. I switched to php5 as my default at the host site and re-uploaded my php files. After about three days I started to get the one-a-days again from same general email address. So?you got a way to fix this? I used Dreamweaver CS5.5 to design the site and have "Spry" client side validation for the forms but I just don't know the php code well enough to do server side validation?or even if that would work. I've looked at adding CAPTCHA but again, don't know the code well enough to add taht either. Let me know what you think. Here are the three site pages that contain the three forms and I can email the php pages associated with them. <[login to view URL]> <[login to view URL]> <[login to view URL]>