No trouble, although this should have been in the QnA section.
Read these:
Pentium Dual Core-
1. *www.intel.com/products/processor/pentium_dual-core/index.htm
2. *en.wikipedia.org/wiki/Intel_Pentium_Dual-Core
3. *en.wikipedia.org/wiki/List_of_Intel_Pentium_Dual-Core_microprocessors
Core 2 Duo-
1.*www.intel.com/products/processor/core2duo/index.htm
2. *en.wikipedia.org/wiki/Intel_Core_2
3. *en.wikipedia.org/wiki/List_of_Intel_Core_2_microprocessors
The Pentium Dual Core in short is a severely cut down version of the Allendale Core 2 Duo processors, which has been discontinued.
Currently, the Pentium Dual Core e5200 has been released which offers quite a performance. The Pentium Dual Core processors are much cheaper than the Core 2 Duos.
Performance wise, the Core 2 Duo is superior.
Core 2 Quad-
Well, Core 2 Quad is just 2 Core 2 Duo's put together ( in simplest words ).
It offers greater performance in multi-tasking, etc. but lags behind in gaming as games are not able to fully utilize the 4 slower cores in a Core 2 Quad compared to 2 much faster cores in a Core 2 Duo.