I also faced the same problem a few months.It continued for 3-4 days.Then our system admin tried to rectify the problem but failed and ultimately we had to upload every thing.
I'm using Windows XP and Photoshop 5.0 LE. All was working well. I turned off my computer for a few hours. When I went back to work on my Photoshop project, the brushes would not show as brushes, when I tried to work with them. They show as cross hairs when I use the clone tool, or as the pencil when I use that tool. My Cap Lock is not on. Please let me know how I can get my brushes to show again.