Ugh, PCs are lame.
Also, this is easily googleable I'm sure.
I don't know how to do so on PCs really bc I edit metadata on iPhoto.

But I used Microsoft Photo Info to edit at an internship once, if you have that.
If you're going the photoshop route though File/File Info lets you edit some. I don't think that lets you edit what you took the picture with though, but it can be done w/ Adobe Bridge...and a shit load of other free programs you can Google downloads/directions for. lol