Walter from Wilmington,De. U.S. writes:
First let me say I am over 70 years old and don’t know much about computers and I would be grateful for any help you can give me.I have been buying and selling on Craigslist for a long time without any problems with my Hotmail e-mail account. Now something has changed, when I click on reply a Window opens with a message that says Internet Explorer cannot perform this operation because the default mail client is not properly installed. Thanks for any help you can give an old man. – Walt Sr.
Lucky for you Walt there are a few good options to fix this. First is to go to the Tools Menu, click on the Programs tab then click Set Programs. Click on set your default programs and choose Hotmail if it’s available in the mail settings.
A better (and more permenant solution as Microsoft keeps breaking/removing options from IE) is using Microsoft’s free Windows Live Essentials E-mail client. You can download the client for free by going here: http://windows.microsoft.com/en-us/windows-live/essentials-other-programs 
Once you’ve downloaded and installed essentials the process to set up Mail is quite simple. Open Mail from your Start menu. In your Mail inbox, click Accounts and then click Email. Type your email address, password, and display name, and then click Next. Mail will automatically detect and configure Hotmail, Live.com, Outlook.com and many other popular e-mail services.
You can still access your mail by going to Hotmail.com but the new Windows Live Essentials Mail client will speed things up and let you send e-mails easily by clicking on addresses in your web browser.
P.S. Need more help with Windows Essentials? Click here  for Microsoft’s support site for Windows Essentials.