I plugged the flash drive (USB) to a friend computer and it does not appear in My Computer.

The reason is the new USB drive letter is conflict with the current drive letters in the computer. Goto Control Panel/Administrative Tools/Computer Management, select Disk Management. You'll see the USB drive appear there (check the size of the drive). Right click on that drive, select "Change drive letter and paths", and choose a drive letter that not conflict with any current drive.

Close the window, and you'll see your drive now appear in your My Computer !

How to enable/disable add-ins in Outlook

When you start Outlook 2003 you may receive error messages similar to this: "The add-in could not be installed or loaded".

Programs like ACT, Plaxo can integrated in to Outlook and install add-ins dll files to your Outlook. Outlook searchs for those add-ins when it starts. If you no longer use those programs and remove them improperly, the add-ins are not available and Outlook will display annoying error messages.

To diable unused/error add-ins in Outlook 2003, go to Tools/Options, select Other. Select Advanced Options..., press Add-in Manager, and then disable add-ins that cause the problem.