i have Intel motherboard "dq41rq" and i want to update my processor to core 2 quad ones. currently i have core 2 duo 2.93 GHz speed. i searched Google but i cant find if my mother support core 2 quad family processors. i don't think if my board support the newer processors of core i series, but i want to update it with old core 2 quad processors.
In regards to finding out about CPU compatibility, usually the motherboard manufacturer does present a list of compliant processors on it's website so it's always best to start there (regardless of brand).
To answer your question, yes it does. You need to check from the official site.
On that page, you can filter by family. In there is an option to choose quad.
For example, Q9650 is Core 2 quad.
This link above shows what processors are compliant with your board! Whilst I don't believe this list is full and that other CPU's not listed won't work, if you go with something on the list, then you know you will (should?) be buying something which will work!