New to HTPC and need some input.

Hello! This is my first post. I have been researching this site for the last couple months while i'm putting together my first htpc. I've read just enough to be reasonably confused and a little dangerous. Here is what I have assembled so far.

Old HP dc7100 sff - P4 3.0ghz with 2 g of ram - (I know it's psu is underpowered, light on processing power and runs hot... but it was cheap)
stock dvd player
SAPPHIRE 100253HDMI Radeon HD 4650 512MB 128-bit GDDR2 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Low Profile Ready Video Card (from newegg) (after researching here)
320 gig western dig HD sata (from dead pc)
Media center wireless keyboard and mouse with IR receiver. (used eBay)
Windows 7 ultimate


My other equipment consist of:
50" Samsung plasma
jvc home theater receiver about 5 years old (decent)
1 - 100 watt sony 10" subwoofer (not bad)
1- passive realistic 12" sub that i installed a 150 watt plate amp in. (it really rumbles)
1 set of Linn Keilidh towers for the front (awesome)
1 set of jbl satellites for the rear (good sound)
1 old realistic car box speaker for the center( cheesy I know but was laying around garage)
HDHomerun - 2 tuner (used on ebay)


I am trying to accomplish the following:
1. Watch movies dvd and BD that are stored on my NAS.
2. Listen to my music collection stored on NAS.
3. Get rid of the cable dvr and use the htpc for watching and recording tv. (will keep TW cable for now)
4. Not a big game player but my son (6 years old) likes to play online games sometimes. (be nice to play a lighter game once and a while)
5. I would like to achieve excellent video and audio performance from this system for as little as possible.


Questions:
1. Will all play well together?
2. Best way to hook vid to tv?
3. best way to hook sound to receiver for surround?
4. do i need a sound card?
5. Software? (planning to use media center for now)
I really appreciate any opinions or suggestion you may have. My vid card should be here in a couple days and hope to fire it up for the first time

Thanks,

Brett

200 watt power supply? is that right?
yes... 200 watt psu. Wish I had researched that a bit more prior to buying. i can't upgrade either because in the small form factor case, the psu is odd shaped. I can only hope that the psu actually puts out more than it's rating. I already bought the vid card too. Hope its not a mistake. should have posted ?'s sooner.

do you have access to the chipset drivers for the computer?

I installed the latest drivers when i install windows 7 ultimate. everything seems to work just fine after a little searching & tweaking.


also, i assume your getting the audio out from the hdmi connector of the vid card, since this computer doesn't appear to have spdif output.

the audio was a big question for me. I am new to home theater and not sure how to hook it up to my jvc to get full surround soung. (all the speaker lights lighting up) (sorry... i really am new to this)


does your reciever have hdmi input/switching?
I am not sure what this is. I think (not sure) on my dvd player setup the sound went through the tv and back to the receiver via an optical cable. It's been a while cause everything was unhooked after my son was born and not put back since so I could be wrong.

My receiver is a JVC-6000V. My tv is a Samsung HP T5044.

basically, i would like it to have full surround sound with bd capability.