Dear Chimera Team: I think your work on Chimera has been of very high quality. In fact, I've used it to produce print quality images for an upcoming book of mine. However, I've had some problems with displaying some large molecules, for example, 1AYM and 1P5Y. I use the PDB file for the molecule, but specifically the assumed biological model file, not the the asymmetric unit file. I've been able to open the file in programs like Deepview and Raswin, but I can't open the file in Chimera. I'm running Windows 98 with about 256MB of RAM, and what happens when I attempt to open the assumed biological model file Chimera runs for over an hour trying to open the file and then crashes with a page fault message. I certainly would like to use the image capabilities provided by Chimera, so can you help me with this? Or is this simply a limitation of Chimera?