i just built a new htpc yesterday and today i tried installing vista. the vista install goes good until the computer restarts and goes to the completing the installation screen. at that screen the computer doesn't freeze but hangs there doing nothing.

my specs are
gigabyte 780g motherboard
amd 5000+ cpu
saphire 3450 video card
2 gigs of ddr2 800 ram
500 gig wd hard drive
auzentech xplosion soundcard

i tried taking out the video card, sound card and 1 gig of ram and it still hangs in the same spot. i also tries disabling things on the motherboard like sound and lan. ive had no luck

the system is not oc'ed or overheating

Seeing that you have already taken out the sound card / video card / extra RAM / diabling onboard sound and LAN.................

Make sure your extra USB connectors (USB to the front / top of case) are unplugged as well.

Install with just CPU / MB / RAM / HD / DVD drive........if this still fails, you might wanna try using this disc on a known working system to make sure the disc is OK

From my personal point of view and the fact you have 2GB of RAM not being able to install Vista should be seen as a good thing.
Vista is this decades MS ME OS...with a few less "bugs".

MS today said (again) that it will keep saleing XP and a new XP with SP2 disk is under $90 USD (often Tax free and free shipping as well) if you had to buy it online....and -everything- runs on XP 32 bit without issues.

I own -two- copies of XP OEM Builder Disk sets,one with SP2.
I use them mostly for myself for my home 7 unit game LAN but also for anyone who wants to pay me $300 USD over parts to slap a rig together and spend a week to OC and fine tune the damn thing.

This old mans personal views aside:
You can also try removeing the sound card (Vista may hate it...in fact on the Creative site it is well known to do so) and onboard sound from most modern MB's is just as good anyhow.
Your sound card uses Creative parts and basicly the same drivers under another name and are well known to be almost compleat crap with Vista....your MB's onboard sound should work just fine however.

In March of 2007 MS said it would end new support for Vista at midnight December 31,2008.
Unless they change thier minds any issues/problems with Vista not addressed by that point is just too bad for those who bought/downloaded it...and don't expect any software developer to support a dead/realitivly rare OS after that date.
Armed that info and with the fact that MS said today it will not end sales of XP this June and make of it what you wish.

MS knows what the problems are and what the public wants....and follows the buyers money...and they stated last year they do not plan to invest money on Vista after the end of this year.