During battles, the yellow text that pops up to indicate damage dealt/received seems to have overlapping issues. Here is a screenshot to show an example:

http://imageshack.com/a/img69/4498/zkst.jpg

Is this a problem with newer video cards (Geforce GTX 760) or Operating systems (Windows 7 HP 64 bit) or something else??

I got the same thing on a nVidia n480, on Vista x64, so I don't think it's a new issue. I think there's another post in the forum about it, overall though I didn't find it much of a problem. The numbers look a bit confusing, but the relative impact is pretty clear, so you can see proportionally how useful a particular effect has been.

It's an issue specific to the gog version. You can choose to display either dmg done or number of units killed through the .ini, but if try both they'll overlap.

http://www.gog.com/forum/kings_bounty_series/damage_display_covers_the_killcount_in_combat_anyone/page1