Just curious Sylvia, did you reference the actual instruction sheet kept in manila type folder or a scan of the instructions in a folder on your computer? 
No, not on the PC - that would have been even easier though!

I keep most of my instruction sheets in plastic sleeves (or "poly pockets," as my kids call them) in a spiral bound folder. I started this many years ago - well before Heather created PlaymoDB - as a way to quickly find a part number without having to find the actual set.
I have so many sets that I stores small sets inside larger set boxes, plus some are in high cupboards which I can't reach without a stepladder.