Can't find old files after upgrading Windows7

I know they're supposed to be in the Windows.old folder, but there is none. Granted, I should've backed up all the files, but I just did a Vista to Windows 7 upgrade on my computer a couple of weeks ago and didn't have this issue. Did everything the same.

Any suggestions?

-I'm thinking that some data recovery software might help out a bit.

Thanks,

Wade.