Thanks to:
HTTP://techsupportalert.com/issues/al_current.htm

The lack of tabs in Windows Explorer is a real liability. Indeed, it's one of the main reasons why many users install an Explorer replacement such as XYPlorer and UltraExplorer.

However, not all users are comfortable straying from the standard Microsoft setup. For these folks there is some good news: It's quite possible to add tabs to Windows Explorer itself by using a free utility called QT TabBar. As a bonus, you'll not only get tabs but a few additional features, such as instant file viewing, thrown in as well.

I've been using QT TabBar on one of my PCs for a week now and have seen enough to be able to say that many PC users are going to VIEW this as a great productivity tool. However, if you are already using an Explorer replacement like XYPlorer, then it's unlikely QT TabBar is for you.

QT TabBar may work well, but setting it up using the supplied instructions can be frustrating. So I've written a simplified guide. Before proceeding, note that QT TabBar only works with Windows XP and Vista. If using XP, the Microsoft .NET Framework V2.0 or 3.0 must also be installed.
Installation Guide:

(a) Go to QT TabBar site and download the ZIP file. (633KB)

(b) Locate the downloaded file; it will be called something like QTTabBar_glb_1.1.0.1.zip.

(c) Double click the ZIP file and extract the contents to a folder called QTTabBar on your desktop.

(d) Close the ZIP file and open the folder QTTabBar and double click the file QTTabBar.exe to install QTTabBar. When installing, accept the defaults.

(e) After installation, log off and then login again or simply reboot your PC.

(f) Open My Documents, click on View / Toolbars. If there is a check against Lock Toolbars then click on it to unlock the toolbars

(g) Click on View / Toolbars. Click on QT TabBar to ENABLE that toolbar.

(h) After a few seconds the QT TabBar will appear. Use the handle at the left of the TabBar to drag and drop the TabBar down and to the left so it is the last visible toolbar.

(i) Click on View / Toolbars. Then click Lock Toolbars to relock.

(j) Move the folder QTTabBar from your desktop to somewhere safe such as c:\program files just in case you want to uninstall the product. How do you uninstall it? By installing again and selecting the uninstall option.

You are now ready to try QT TabBar. While still in your "My Documents" folder let's open some new tabs. You can do this several ways:

- The simplest is to middle mouse click on a folder

- If you have no middle mouse button double click a folder while holding down the Shift key

- Drag and drop a folder onto the tab bar

- Double click a folder shortcut on your desktop

You can easily navigating between open tabs by clicking the tabs on the tab bar. You can also re-order tabs by dragging and dropping.

Imagine how much simpler this makes copying files from one folder to another or carrying out any form of file maintenance. But there's more to come:

As soon as you start using QT TabBar you'll notice a little blue arrow appearing beside your folder entries. Clicking that arrow shows the contents of the folder. If that folder contained sub-folders then a series of cascading drop down menus will open out if you click the sub-folders.

And now a really nice feature: hover over any plain text or image file and you'll see the text or image displayed.

There are quite a few other niceties as well, but I'll let you discover them. Of course, if you are desperate to KNOW you could always read the manual :>)

One feature is not quite so nice. I had trouble fully uninstalling QT TabBar from one of my PCs. In could be a problem with that particular PC but just to be certain I SUGGEST you install QT TabBar while the install is being monitored by an uninstaller such as the free ZSoft uninstaller [2] or Revo [3]. Mind you, I suspect you won't be uninstalling QT TabBar any time soon :>)

[1] QT TabBar: Freeware, Windows XP and Vista + NET 2.0 Framework, 633KB.
http://quizo.at.infoseek.co.jp/freeware/indexEn.html#qttab

[2] ZSoft Uninstaller: Freeware, Windows XP, 896KB
http://www.zsoft.dk/

[3] Revo Uninstaller: Freeware, Windows 2000 -> Vista, 1.34MB.
http://www.revouninstaller.com/
If a program needs to be monitored to be uninstalled correctly it's not ready for prime time...i think i'll pass on this one...I'm not seeing how QT TabBar is worth the trouble of installing.  While having two Explorer windows open is often helpful in moving files/folders from one location to another, a tabbed Explorer would still display one tab at a time.  Right?  So, switching from tab to the other would still be necessary and, in my opinion, less helpful than having two separate Explorer windows open that I can resize in a way that allows me to see both at the same time. 

Or, with my dual monitor setup that I run with my desktop system, I can open an Explorer window on each monitor.  Quote

If a program needs to be monitored to be uninstalled correctly it's not ready for prime time

This is great!!   Just installed it.  I always have alot of explorer windows open at the same time and it would clutter up my start bar.  now i can have as many folders open at once as i want and it will only take up one spot on my start bar.