<p>FogBugz requires that Data Execution Prevention (DEP) be disabled when installing on Windows Vista.</p>
<p><strong>How to disable DEP:</strong><br />

<ol>
<li>Click the Start button.</li>
<li>In the Start Menu, navigate to All Programs, then Accessories.</li>
<li>In the Accessories menu, right click on "Command Prompt" and select "Run as administrator."</li>
<li><em>You may need to provide Administrator credentials at this point.</em></li>
<li>In the Command Prompt window, type "bcdedit.exe /set {current} nx AlwaysOff" and press Enter.</li>
<li>You should see "The operation completed successfully."</li>
<li>Close the Command Prompt.</li>
<li>You <b>must</b> then reboot your computer. Failure to do so will cause weird problems later on.</li>
</ol>

<p>If you still run into problems, you can run setup from the command line like so: <b>setup.exe /ignoredeperror</b></p>

<p>Note: if you ever need to enable DEP again, you can follow the same steps except provide "AlwaysOn" as the final parameter to the bcdedit.exe command in the Command Prompt.  Be warned, however, that FogBugz will not function properly with DEP enabled.</p>
<p>These steps and more can be found here: <a href="http://vistasupport.mvps.org/disable_data_execution_prevention.htm">http://vistasupport.mvps.org/disable_data_execution_prevention.htm</a>.<br />Extended information about DEP can be found at Microsoft's site: <a href="http://support.microsoft.com/kb/875352">http://support.microsoft.com/kb/875352</a>.</p>