It would help if you were to provide that spec for your computer, make and model, amount of RAM...
Both of your hdds are full, what is remaining is being used for swap space, if you have a insufficient amount of RAM and try to do things that are resource intensive your system will try to use the free space in you hdd to take up the slack.
I don't know what you have on those hdds, but you may want to do a little selective cleaning, and save other less often used files, picture, and movies to CDs or DVDs. Or just get a bigger hdd if you need what's on there.