Drag n Drp

Hi this is my first Macbook....had it a couple of months now.......transition was going great.....just upgraded to the latest software (10/10/15), and I seem to have lost the ability to drag n drop in 'Photos' any idea how to get it back.
Any help appreciated....

Glad you are enjoying it! I presume you mean "10.10.5" rather than 10/10/15, as that date hasn't happened yet ... or maybe you're from the future ...

That is of course NOT the latest software ... Yosemite has now been replaced with El Capitan (10.11), so you may want to see if updating again fixes the issue, but first I'd suggest a simple restart, a run of OnyX and a full backup before upgrading. Might fix the problem as well.