is my intel core 2 duo cpu @ 2.0 Ghz able to run something that requires "2.6 GHz Pentium® IV or equivalent"?

Yes. Clock speed doesn't really matter anymore. There are so many transistors on the newer CPUs that they don't need to be anywhere near the frequency of older chips.

No, it doesn't really work that way. Taking a 2 GHz core and fitting it next to another 2 GHz core didn't process like a 4 GHz core at all. That's because the second core needs specific software to process at the same time.

One bit has to follow the other. If you try to process one bit on this side and the next bit on the other side, the computer will get confused and process nothing at all, just like a cash register operator trying to serve two customers at once.

The speed depends on the software and what platform it was written for. Less than 1% of all popular software applications could handle the second core. The ones that can, like Adobe Photoshop, will absolutely fly! On a 3 GHz per side dual core, Photoshop performs like it was accessing a 6 GHz single core or even better than that!

However, most other software, games, etc. just don't even recognize the second core and keep plugging along at normal speed.

The great thing about dual core is that you can run one application on one core and the other application will run on the second core so that combined, the two run much faster on a dual-core processor than they would if you were using both applications simultaneously on a single-core processor.

So if the software says it requires 2.6 GHz, I would make sure the speed of each core is 2.6 GHz. Whether it will run on a slower dual-core depends entirely on the software.

Simple answer .... Yes.

you have a intel core 2 duo means you haev 2.0 times 2. so you have almost 100% more than what is required.

yes

multiply your core x2