You may want to check out the fix packs, I believe for 19 one of the issues was with copying-pasting. Although to be honest if you are copying pasting a lot you should probably re-think your workflow (i.e. figure out how to import the data directly into SPSS).
Two may need more clarification (I have no idea what you are talking about), and three I can't answer because I honestly don't know what the undo keys should undo exactly (although again you should provide more clarification). It sounds as if you are performing operations directly on the data spreadsheet. It would be best IMO to learn the syntax language to perform operations.
Of course this doesn't help when entering in data, but entering data in spreadsheets should be limited (anything complicated/lengthy and you should build user-forms IMO).
Andy