What to do when the computer's CD/DVD doesn't play smoothly

Since three months ago, when I decided to format my laptop's HD and reinstall Windows (ahem... the reasons for doing so are reserved to myself), I've noticed a very disturbing and annoying phenomenon: When I played some music CDs and all kinds of DVDs, the sound (or in case of a DVD - the movie) was played unstably. Also, the slow burning speed was reasonless.

For the purpose of demonstration, say I wanted to hear the song "I walk beside you" of Dream Theatre from their masterpiece album "Octavarium".

Normally, it should be sound like this:

"...Summon up your ghosts for me / Rest your tired thoughts upon my hands / Step inside this sacred place / When all your dreams seem broken..."

But actually it was heard more like:

"...Su____mmon up yo__ur gho___sts fo _r me / Rest you___r tir_ed thou__ghts up on my hands / Step inside th__is sacred place / Wh__en all your d__reams seem bro__ken...".

It is that song that sounds broken, damn it!
Therefor, I decided to take a long breath and fix this thing once and for all. So I thought for the most possible reasons:

• The DVD's reading ocular is dirty
• The CD is scratched
• There's some copyright feature that causes this
• Codecs conflict cause a distort playback
• "Nero" become crazy
• BIOS problem
• Driver problem

Instantly I rejected the first three options, since I already cleaned up the reading ocular, the CD is as good as new and it is completely genuine and legal.
So for the Codecs issue, I started to isolate each codec by uninstalling one by one, but it didn't solve the problem.
About "Nero": It wasn't the only CD burn software that has the problem of slow burning operations, every software acted the same.
Next, I searched for an update to my laptop's BIOS. I seached for a compatible BIOS for the HP Pavilion dv5000 series, and I found it here (F.54 of Phoenix Technologies). After installing the update (I was surprised it went very fast and without any problem...) and restarting, I found it didn't solve the problem. Dirty.
Next is driver: Well, I searched the web for a drvier update, but I already had the latest version.

Ok, so here is what DID solve the problem:
It is the IDE ATA/ATAPI controller. Each IDE device (for example, a CD drive or a hard drive) can work under Windows in two modes. The first is called "PIO" (Programmed Input/Output. read more here) and second is called "DMA" or "UDMA" (Direct Memory Access. read more here).
To make a long story short, The PIO is the older technology for data transfer from a hardware to the physical memory while the DMA and UDMA are newer and much faster methods to do the same operation.
So from some reason, the IDE channel for the CD/DVD drive was set to work in PIO mode. Also, I couldn't change it to UDMA. So what I did is:

1. Go to the Device Manager
2. Under "IDE ATA/ATAPI Controllers", right click on "Standard Dual Channel PCI IDE Controller" and then "Uninstall".
3. The Windows asked me to restart
4. After the restart, a "new hardware" was discovered and installed automatically.

And like a magic, all IDE channels worked on a UDMA mode.
Everything is now working properly and I can hear "Octavarium" smoothly!