Removing software in Windows can lead to filetype associations getting scrambled. For example, when you uninstall ACDSee it doesn't restore picture file associations causing pictures to no longer open in Fax and Picture Viewer in Windows XP. Instead, pictures are opened in MS Paint when you double click on them. This is fine if that's what you really want. Otherwise, restoring Fax and Picture Viewer as the default program to view pictures when you click on them is just a simple command away:
:\> regsvr32 shimgvw.dll
Click OK on the dialog that appears, and Fax and Picture Viewer should be restored as the default program to handle picture viewing.