Ati radeon hd5450 vga no sound

? VGA stands for Video Graphics Array. There is no option for sound. You need to plug into some speakers with "normal" 3.5mm plugs. (or USB if the speakers use those.)

yeah but my computer has a built in speaker

So? How do you expect the sound information to get there? I'm assuming you mean your monitor has a built in speaker. If you are talking about a speaker in your computer case it doesn't work like that. That speaker is only for bios beeps, not sound. If your monitor has speakers, you need a cord that has a 3.5mm "phono" plug on both ends. Plug it into your speaker jack on your motherboard and the monitor. Make sure you have your Sound Card drivers loaded as well.

i have a speaker in the case that is for sound i use to use it when i used my onbored graphics

In which case I'm not following. I'd need system specs for what you had and now have.

hp dc770 sff
intel pentium d 2.80 ghz (2 cpu)
2 gig of ram
windows xp
ati radeon hd 5400 series

i have tried connecting hdmi to my tv there is a sound card driver for hdmi but there is no sound playing through tv

Are the drivers updated?

How can that be the best answer? (no offense to amuffin.)

What was the old card when things were working? I thought you said you were trying to play sounds through the speaker in the computer? VGA doesn't support audio. You'll need to use a second cable or switch to HDMI. In either case it won't make a case/tower speaker work.