nub question

i'm having a problem that seems intermittant, as i've had it and fixed it multiple times without noticing... i'm a nub to photoshop and here soz let me explain carefully as i can

i want to edit a photo, so i file > open the photo... one of two things will happen
1) everything is as normal, if i grab a brush tool i can paint overtop of the image, modify a mask or w/e
2) i can select any tool i wish, but hovering over the image displays the 'grabbing' tool (hand) and wont let me modify the image in any way, nor any other layer in the project...

restarting the program multiple times doesent work, also tried saving the file as a jpeg and opening it again....

seems as though nothing i do will allow me to use the tools properly, until at some point cs3 gods will pity me and allow me the use of the tools again...

ideas?

If you press the space bar any tool will turn it into the hand tool. Make certain you are not pressing it, or that it is not sticking.