If you're using Windows XP, I ensure you if you use Windows Explorer every time. To open Windows Explorer, you can press Windows + E keys or go to Start - All Programs - Accessories - Windows Explorer. Windows Explorer has 5 model of column views. Thumbnails, Tiles, Icons, List, Details.

And if you are like me who like set it to Details view, you will often faced with a column or more which don't enough to display the informations. The information can be file name, file size or else. To expand them, usually I click column header and then drag it until they are expanded.
But to make it easier you can press Ctrl + [+] keys to make them expanded. I suggest you to press the [+] key where located on numpad group.