Create a Lock Computer Shortcut Icon

1. Right click on the desktop, select New > Shortcut.
2. Enter rundll32.exe user32.dll,LockWorkStation as the shortcut.
3. Name it Lock Computer.
4. Right click and choose Properties.
5. Click on "Change Icon"
6. Search through shell32.dll in the System32 directory and find an appropriate lock icon.
NOTE: This effectively dumps you back to the "Welcome" log on screen. Of course this will only work if you have entered a password for your profile.
ADDENDUM: If you want added security, go to the Control Panel and click on "User Accounts". Click "Change the way users log on or off", and deselect the "Use the Welcome Screen" option.This will switch Windows back to the classic log in box.

Change Briefcase icon on NT/W2K/XP

You can change the Briefcase icon and replace it with an icon of a metal attaché case using the following Windows
NT/W2K/XP registry hack:
Hive: HKEY_CLASSES_ROOT
Key: CLSID\{85BBD0920-42A0-1069-A2E4-08002B30309D}
Name: DefaultIcon
Type: REG_EXPAND_SZ
Value: %SystemRoot%\system32\syncui.dll,1  (shiny metal attaché icon)
Value: %SystemRoot%\system32\syncui.dll,0  (default leather Briefcase icon)
Download these registry files already made:
Leather.reg
MetalAttache.reg
After changing to the icon, you may have to log off then log back on or restart your computer for the change to take effect.

Performance Increase through My Computer

Start > Right Click on My Computer and select properties.
Click on the "Advanced" tab
See the "Performance" section? Click "Settings"  Disable all or some of the following:
Fade or slide menus into view
Fade or slide ToolTips into view
Fade out menu items after clicking
Show Shadows under menus
Slide open combo boxes
Slide taskbar buttons
Use a background image for each folder type
Use common tasks in folders