LAPTOP TO AV RECEIVER

Probably a mini jack (small headphone plug type) to RCA/phono -- in other words the standard cable supplied with computer soundcards for connecting speakers etc.
 
Computers usually use minijacks (like a Walkman or iPod heaphone).

The cable I mention has minijack one end and RCA/Phono plugs at the other but you can easily find a cable with minijacks both ends.