yes you would notice a improvement, its a good sound card not the best but good, and all you would need its a optical cord for digital if your receiver has optical.
he is deffently not getting 3meg on the 1.5mb plan unless they did provision his line wrong, but if he is infact on the 1.5mbps plan he can not get faster then 1536kbps
make sure everything is seated propally, memory, processor, all pci cards, sata ide cables. all power connectors are in firmly.
then give it another try. if it still does not work, remove 1 part at a time, and turn the computer back on a and see if it comes up. do that till you get down to just the mobo processor and memory.