Your better off without outlook express. The cause of your old hard drive jamming on you could have propably been due to outlook express. How do I come up with such a wacky idea you say? Well, as you have already heard, outlook express downloads all mail INTO your computer, then from your computer opens it up and reads it. It's simple enough to get an e-mail virus, its even easier when the virus was downloaded to your computer, and now your opening it up using outlook express.
Also, it can reduce disk space as happened to one of my dad's helpers. He hadn't checked his mail in 1 month, next time he got on that laptop (50 GB HD) he couldn't save anything cause outlook had saved all his mail to his hard drive and choked the disk space. So, long story short, your better off without outlook express!