With Windows 7 and probably Vista, try the following:
From the Start Menu, in Accessories, Right click on Notepad and select "Run as Administrator." You may well be asked to confirm this.
Once Notepad is loaded, Choose the File Open menu option and navigate to c:\windows\System32\drivers\etc
Change the dropdown "Text Documents (*.txt)" to "All Files" and you should see the file hosts. Open this file.
Add the line 0.0.0.0 nwmaster.bioware.com as below and save the file.
# Copyright (c) 1993-2009 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host
# localhost name resolution is handled within DNS itself.
# 127.0.0.1 localhost
# ::1 localhost
0.0.0.0 nwmaster.bioware.com