Crop Tool problem

I run Windows XP Pro SP1 on a P4 3.0,1Gb RAM,ATI Radeon 9600 128Mb video card and shoot with a Canon Digital Rebel. When I open a JPEG from my camera and try to use my crop tool, it doesn't function properly. I should be able to drag left or right from a start point or up or down from a start point and have the box increase in size as I go, correct? My box seems to increase in size only in a diagonal way, never really allowing an actual crop size to take place. The crop box outline doesn't even follow the icon as I move around. I uninstalled and re-installed PSE 2.0 but the problem still exists. Has anyone else experienced this problem or have any suggestions. Thanks for your help.

Thanks Byron. While I was waiting I found the Reset Tool button and that solved my problem. I'm new to the camera and PSE so there is lots to learn. Thanks for the quick response!