I don't know of any conversion programs, Juno's email file format is a bit cryptic. Best way to save the mail is to forward the important ones to a different email account. Juno forces you to use their own Email interface, or a web Interface from their juno.com website.
have her run MSCONFIG from the start menu and then disable some of the startup items and see if that makes a difference. Windows 98 has this, just have her hit the Start menu, and choose the Run command and then enter MSCONFIG into the text box and hit run. Then get to the Startup tab and have her read off the ones that are checked. Or better yet, have her disable all of them except for Scan Registry, Systray, and whatever AntiVirus software she is using. If she uses a Winmodem, be sure to keep that one checked as well. Keep the "Juno*" ones checked if they are there. See if this solves the problem.