I have an acer Extensa 5220 and has run out of room so can't install anything else on it. How do I increase this? I haven't got a clue

This ISN'T a memory issue at all, but one of hard drive space.

Time for a clean up.
I'd use CCleaner (http://www.ccleaner.com) for starters and remove all of the junk files from your system. Then have a look at your installed programs and uninstall any you no longer use.

Once this is done, it's time to archive your data.
Music and pictures take up a lot of room, so best to burn them to CD for storage.

Oh right, thanks. Also I have this other Acer laptop one that has pretty much died out of too much use, is there anyway of taking the stuff out of that to increase this current laptop?