Audio Device not found ??? and also can't hibernate/stand by

Hello,
I reformatted my HD and reinstalled xp because I was having all sorts of
freezing problems.
After reinstallation, I got no audio sound and after checking in Control
Panel, it says that there is no Audio Device found/installed.

I downloaded the original hp driver for the audio device, but when
installing it, it says to go to device manager, find the device, and from
its properties, select "update driver". Well, I don't find my device there.
I only find Audio Codecs, Legacy Audio Drivers, Legacy Video Capture
Devices, Media Control Devices, and Video Codecs. And I don't know if any
of those choices are really my "audio device". So, I was hesitant to do
anything.

I checked in the BIOS and the on-board audio is enabled as hp says it should
be for my computer.

I tried to download Windows updates to see if that would help, but every
time it scans my computer to see what updates are available, it disconnects
me from the internet - apparently because of a discrepancy in my clock/date
settings, but all is normal after checking those settings. I followed their
troubleshooting steps as to why the disconnect, but it did not help.

I scanned my system for viruses and all is ok.

Any ideas?

By the way, another "issue" after reinstalling windows is that my option to
"stand by / hibernate" is grayed out and therefore unavailable.

Background info:
I am running WinXP pro sp1
my hp is a pavillion a250n, P4, 2.6 GHz
I tried hp system restore cd and after finishing all the steps, it said that
system32/hal.dll was missing or corrupt and therefore windows could not
start. For that reason, I had to use my "older" winxp pro cd (from 2002)
and did a new install with partition reformatting.

I appreciate your time and any help.
AM