Photoshop won't open certain images...HELP!

I have been using CS3 for the past year and everything has worked great. Lately I get the error message when trying to open certain jpgs "Could not complete your request because there is not enough memory (RAM)"
The weird thing is that I edited a bunch just the other night, but now can't open them in photoshop...but I can open previous jobs with no problems. Why can I not open certain images?!?!?

I have no idea what to do!!!
I also get an error message when I try to close photoshop "Cannot export clipboard because there is not enough memory (RAM)"

Please help, it's driving me batty!!!

Thanks