Windows XP and Windows XP SP1: Edit the registry and install Internet Explorer 6
Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

When you try to reinstall the same version of Internet Explorer, you may receive the following error message:
  Setup has detected a newer version of Internet Explorer already installed on this system.
Setup cannot continue.

To avoid this error message and reinstall the same version of Internet Explorer and Outlook Express, follow these steps:
1. While you are logged on as an administrator, click Start, and then click Run.

2. In the Open box, type regedit, and then click OK.

3. Locate the appropriate registry subkey, right-click the IsInstalled (REG_DWORD) value, and then click Modify.

  To reinstall only the Internet Explorer 6 browser component on Windows XP, use the following registry key:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{89820200-ECBD-11cf-8B85-00AA005B4383}
To reinstall only Outlook Express 6 on Windows XP, use the following registry key:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{44BBA840-CC51-11CF-AAFA-00AA00B6015C}

4. Change the value data from 1 to 0, and then click OK.

5. Quit Registry Editor, and then install Internet Explorer 6.  

6. To reinstall Windows XP updates, visit the following Microsoft Windows Update Web site:
http://windowsupdate.microsoft.com/ (http://windowsupdate.microsoft.com/)

By default, Internet Explorer 6 is preinstalled in all versions of Windows XP and cannot be removed. To provide computer manufacturers more flexibility in configuring desktop versions of Windows XP, Microsoft has made it possible for OEMs, administrators, and users to remove user access to Internet Explorer while leaving the Internet Explorer code intact and fully functional to make sure the functionality of programs and operating system functions that rely on it. For example, Windows XP supports an "IEAccess=off" switch in the Unattend.txt file, and Internet Explorer has been added to the Add/Remove Windows Components section of the Add/Remove Programs tool in Control Panel. This does not reinstall Internet Explorer.

編輯登錄並安裝 Internet Explorer 6
警告：不當使用「登錄編輯程式」可能會導致嚴重的問題，甚至必須重新安裝作業系統。Microsoft 並不保證可以解決您不當使用「登錄編輯程式」所導致的問題。請自行承擔使用「登錄編輯程式」的一切風險。

當您嘗試重新安裝相同版本的 Internet Explorer 時，可能會收到下列錯誤訊息：
安裝程式偵測到這個系統已經安裝更新的 Internet Explorer 版本。
安裝程式無法繼續執行。
如果要避免出現此錯誤訊息，並重新安裝相同版本的 Internet Explorer 和 Outlook Express，請按照下列步驟執行： 1. 以系統管理員的身分登入並按一下 [開始]，再按一下 [執行]。
2. 在 [開啟] 方塊中，輸入 regedit，然後按一下 [確定]。
3. 找出適當的登錄子機碼，以滑鼠右鍵按一下 [IsInstalled] (REG_DWORD) 值，然後按一下 [修改]。

如果只要在 Windows XP 上重新安裝 Internet Explorer 6 瀏覽器元件，請使用下列登錄機碼：
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{89820200-ECBD-11cf-8B85-00AA005B4383}
如果只要在 Windows XP 上重新安裝 Outlook Express 6，請使用下列登錄機碼：
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{44BBA840-CC51-11CF-AAFA-00AA00B6015C}
4. 將值的資料從 1 變更為 0，然後按一下 [確定]。
5. 結束「登錄編輯程式」，然後安裝 Internet Explorer 6。
6. 如果要重新安裝 Windows XP 更新，請造訪下列 Microsoft Windows Update 網站：
http://windowsupdate.microsoft.com/ (http://windowsupdate.microsoft.com/)
根據預設，Internet Explorer 6 會預先安裝在所有的 Windows XP 版本中且無法移除。 為了讓電腦製造商更彈性地設定桌上型 Windows XP 版本，Microsoft 已開放讓 OEM、系統管理員和使用者移除 Internet Explorer 的使用者存取權，同時保留 Internet Explorer 程式碼原封不動且功能完整，以確保程式的功能以及倚賴它的作業系統功能。 例如，Windows XP 支援 Unattend.txt 檔中的 IEAccess=off 參數，而 Internet Explorer 已新增至 [控制台] 中 [新增/移除程式] 工具的 [新增/移除 Windows 元件] 區段中。但是這樣不會重新安裝 Internet Explorer。