Lr 4.3 woes

Lr 4.3 does not list PsCS6Ext as an editing preference when you right click on a picture and the editing window opens; it does show PsCS4 as a preference. I deleted CS4, CS5 and previous Lr programs after I downloaded the new PS CS6 Ext and Lr 4.3. I deleted the previous programs because the new programs became unstable and now are to the point that I cannot edit with them. I was told, (by an Adobe support rep),  that the previous versions were probably causing the instability. Clearly I need more direction as things have gone from bad to worse.