In VMWare Player on Win7 can't expand my virtual OS's disk even though I have 10GB free on my Win7 file system

OK I figured it out. VMWare Player doesn't expand your disk in place. It creates a new file of the new size then copies the contents of the old file to the new file. So if you want to expand from 16GB to 20GB, you need 36GB, so that a 16GB file and a 20Gb file can coexist while the contents of the 16GB file is copied over to the 20GB file