How to Change Default Folder of Windows Explorer

Create a custom Explorer shortcut
1a. Start, All Programs, Accessories, Windows Explorer
1b. Quick Launch bar or Desktop, Windows Explorer
2. Shift Right-click on Windows Explorer, Properties, Shortcut tab.
3. Text box after “Target”:

Custom: %SystemRoot%\explorer.exe /n, /e, <New Path>

Show all top–level drives and folders: %SystemRoot%\explorer.exe /n, /e, /select, <New Path>
Default: %SystemRoot%\explorer.exe


i.e.
always open in “C:\MyFolder” then %SystemRoot%\explorer.exe /n, /e, C:\MyFolder\
always open in My Documents then %SystemRoot%\explorer.exe /N,::{450D8FBA-AD25-11D0-98A8-0800361B1103}

4. Click OK.


Special Folders/Directories:

CLSID
Meaning/Location
::{d20ea4e1-3957-11d2-a40b-0c5020524153}
Administrative Tools
::{85bbd92o-42a0-1o69-a2e4-08002b30309d}
Briefcase
::{21ec2o2o-3aea-1o69-a2dd-08002b30309d}
Control Panel
::{d20ea4e1-3957-11d2-a40b-0c5020524152}
Fonts
::{ff393560-c2a7-11cf-bff4-444553540000}
History
::{00020d75-0000-0000-c000-000000000046}
Inbox
::{00028b00-0000-0000-c000-000000000046}
Microsoft Network
::{20d04fe0-3aea-1069-a2d8-08002b30309d}
My Computer
::{450d8fba-ad25-11d0-98a8-0800361b1103}
My Documents
::{208d2c60-3aea-1069-a2d7-08002b30309d}
My Network Places
::{1f4de370-d627-11d1-ba4f-00a0c91eedba}
Network Computers
::{7007acc7-3202-11d1-aad2-00805fc1270e}
Network Connections
::{2227a280-3aea-1069-a2de-08002b30309d}
Printers and Faxes
::{7be9d83c-a729-4d97-b5a7-1b7313c39e0a}
Programs Folder
::{645ff040-5081-101b-9f08-00aa002f954e}
Recycle Bin
::{e211b736-43fd-11d1-9efb-0000f8757fcd}
Scanners and Cameras
::{d6277990-4c6a-11cf-8d87-00aa0060f5bf}
Scheduled Tasks
::{48e7caab-b918-4e58-a94d-505519c795dc}
Start Menu Folder
::{7bd29e00-76c1-11cf-9dd0-00a0c9034933}
Temporary Internet Files
::{bdeadf00-c265-11d0-bced-00a0c90ab50f}
Web Folders



Windows Explorer (default)
%windir%\explorer.exe
Computer
%windir%\explorer.exe /n,::{20D04FE0-3AEA-1069-A2D8-08002B30309D}
%windir%\explorer.exe shell:MyComputerFolder
My Documents
%windir%\explorer.exe /n,::{450D8FBA-AD25-11D0-98A8-0800361B1103}
Documents Library
%UserProfile%\AppData\Roaming\Microsoft\Windows\Libraries\Documents.library-ms
Downloads
%UserProfile%\Downloads
Recycle Bin
%windir%\explorer.exe /n,::{645FF040-5081-101B-9F08-00AA002F954E
Network Neighborhood
%windir%\explorer.exe /n,::{208D2C60-3AEA-1069-A2D7-08002B30309D}
Default Web Browser (ex: Internet Explorer)
%windir%\explorer.exe /n,::{871C5380-42A0-1069-A2EA-08002B30309D}
Computer Search Results Folder
%windir%\explorer.exe /n,::{1F4DE370-D627-11D1-BA4F-00A0C91EEDBA}
Web Folders
%windir%\explorer.exe /n,::{20D04FE0-3AEA-1069-A2D8-08002B30309D}\::{BDEADF00-C265-11D0-BCED-00A0C90AB50F}
User Profile (personal) Folder
%windir%\explorer.exe shell:Profile


Using the Explorer.exe Command Line Syntax/:
%windir%\explorer.exe [/n][/e][,/root],X,[[/Select],Y]

X specifies the object, and optionally with sub-object Y. The /e switch shows the left Windows Explorer tree view in the navigation pane together with the right pane in list view, while /n hides the left navigation pane. When the/root parameter is present, Explorer.exe will explore the root object X and objects belonging to X. On the other hand, when the /root switch is not present, Explorer.exe explores the object X, its children, and other Explorer objects as well. The /Select switch puts the focus on a file or folder.

For example:

Code:
%windir%\explorer.exe /N,%WinDir%\System32,/Select,%WinDir%\system32\calc.exe
The command above will explore the C:\Windows\System32 folder and put the focus on the calc.exe (calculator) program.

Sources:
http://www.mydigitallife.info/how-to-change-windows-explorer-default-folder/
http://www.sevenforums.com/tutorials/2863-windows-explorer-taskbar-icon-change-open-target.html