The HD power/sleep setting cured the problem. Resolved
About 1 month old system from Dell Sleep/hibernate set to system defaults (balanced) occasionally doesn't wake up, the mouse icon is very sluggish keybd doesn't work so cannot enter Pin. No other keybd keys function, after about 5 min the Keybd functions And I'm in. All Dell updates have been done, Support Assist Home page all options run, Trouble shoot for Standby/Hibernate fails, as does Mouse. Did an online support chat and they ended the chat for no reason I might mention I'm using the Dell supplied wireless Keybd & Mouse which frequently reports low battery, when it is not Perplexed 
OptiPlex 7000 SFF Sleep/Hibernate