privacy and hard drive

I want to sell this PC minus the hard drive. Will that guarantee that any personal details cannot be retrieved or are details recorded somewhere else in memory? I understand computers regularly take snapshots? Where are they stored and can they be retrieved without the hard drive

 

Did you leave any CDs (or DVDs) with your data in the cd drive or floppies in the floppy drive?
Is there more than one hard drive in the computer?
Are you selling the computer with any previously used (but erased) media like floppies, CDRW, DVDRW, Flash memory, USB keys (UFD), tape back ups, etc.?
Is your computer a really old gateway with a smart keyboard that could record macros within the keyboard itself?

If you answered no to all the above, then nothing could be retrieved other than the timezone you are in from the BIOS clock and maybe the type of hard drive you last used. No data though. That is all stored on the drive.
RAM memory is cleared on power down.
Hope you sell it!