Here is step-by-step how to block email address (sender) in either Windows Live Hotmail or MSN Hotmail at below. I hope it helps!

Block an Email Address in Windows Live Hotmail
To add a sender to your Windows Live Hotmail blocked senders list:

[list]
[li]Select Options | More Options, (or just Options if no menu comes up) from the Windows Live Hotmail toolbar. [/li]
[li]Follow the Safe and blocked senders link under Junk e-mail. [/li]
[li]Now click Blocked senders. [/li]
[li]Type the undesired email address under Blocked e-mail address or domain: [/li]
[list]
[li]You can block all addresses at a domain — the domain being what comes after the '@' sign in an email address — by entering just that. [/li]
[/list]
[li]Click Add to list >>. [/li]
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Block a Sender by Email Address in MSN Hotmail
To block mail from an email address in Hotmail:

[list]
[li]Select Options from the main Hotmail navigation bar. [/li]
[li]Make sure the Mail category is selected. [/li]
[li]Follow the Junk E-Mail Protection. [/li]
[li]Click Block Senders.[/li]
[li]Now type the address you want to block in the single entry field on the left. [/li]
[li]Click Add >>.[/li]
[li]Now click OK. [/li]
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