Can't open large layered pdf files. Not enough memory

I have a large 300 M layered pdf file that when I attempt to open eventually pops up the "not enough memory (RAM) message.

I am on a windows XP Power Spec computer with 1.97 RAM I have allocated 1106 MB for memory useage, 12 history states and 8 cahce level.

I have a 187 GB Seagate exterior harddrive as my main scratch disk and a mirrored main drive C with 154 GB of free space as my second scratch disk.

I also experience a canvas disapearance occasionally when using the polygonnal lasso tool. I can be clicking along and all of the sudden the image disapears until I click again. Annoying but not unworkable.

Any ideas?

"Not Enough Memory" usually means there's not enough free, contiguous and defragmented scratch disk space available.

exterior harddrive as my main scratch disk

If it's a USB external, that's too slow. It should be either Firewire 800 or eSATA. But a separate internal SATA drive is the best.

For now, try to defragment your drives and see if that helps.

I can open psd and other file formats of equal size but not pdf's. I switched the scratch discs around to see if that helped but still am getting the same issues