Strange P4G8X Deluxe Problem

Originally posted this on a web forum but got no response.

I have a computer built around a P4G8X Deluxe (details at end of post)
running XP Pro which I got as soon as the motherboard was available.

Often, after logging in shortly thereafter (usually 10 seconds or so,
sometimes a bit longer), my computer will lock up. If it makes it past
this point, it usually stays up without further problems, though every
once in a blue moon it will freeze after run in a while (or during
shutdown). I don't know if these last are related or just standard issue
windows blowups.

Additionally, I am getting a wierd issue which my CD/DVD drive. However I
don't know if the DVD drive itself is the problem as it also exibited
itself with a different DVD drive from my old machine which I had put in
there.

Originally I saw the problem when trying to install the game Gothic II. It
would seem to be sluggish responding to the disk, and when I get the
install finally going, somewhere during the process (sometimes make it to
the next CD to install, not always) it would fail with a hard lock. This
is with both the original BIOS, and 1006. I assumed at the time it was
having issues with some copy protection technique, and since I just
borrowed this game from a fried to take a look at it, I didn't worry about
it.

Recently however, I saw the problem with URU Ages Beyond Myst. I
successfully installed and played the game without issue when I first got
it. A few months later, I wanted to play the expansion pack, and my
machine would not reliably read the disk anymore, showing the same
problems Gothic II does.

Anyone have any idea what may be causing these problems?

P4G8X Deluxe
Granite Bay/ICH4/IT8708
ASUS P4G8X ACPI BIOS Revision 1006
Penium 4 3.06 GHz
2G memory [1]
GeForce Ti 4600
HP DVD Writer DVD300i [2]
120G HD (WDC WD1200JB-75CRA0)
Creative SB Audigy 2 (WDM) [3]
Windows XP Pro (I keep up to date on the updates).

[1] 4 sticks of 512M PC3200 DDR. I think. Can't remember exactly what
memory, but I researched memory and used the top rated stuff I could find
(as I recall, it was a tie between two brands).

[2] The box it came in says DVD300xi, front panel of drive says DVD300i,
system thinks it is a DVD300n)

[3] I did recently update the drivers for this. Didn't fix my crash
problem, but on the plus side, WinAmp stopped its occasional stuttering.