My washing machine leaks where the cold water hose joins the blue plastic input thingy. It seems like it is stripped. If I tighten it just "so" it will only drip slightly. If I over tighten it, it actually gets looser and will spray all over. Is there an easy way to fix this or do I have to get someone to come and open up the whole washing machine?

Sounds like the blue plastic part is about to crack if it hasn't already. Try some of that tape... It's plumbing tape that you put on the "male" part of the connection and then gently screw on your hose. It makes a kind of seal or gasket... it looks like first aid tape only thinner and stretchier. It worked for me when my old machine leaked from there--the plastic part was old and brittle but that tape did the trick.
Hope that helps.

Trying nailed it! The tape is Teflon Tape. Put three turns around the male threads and snug up with a pair of pliers. CARFUL! Don't overtighten? Remember you're working with p-lastic threads and you have to be more gentle then would metal ones. Good luck, Tom