Sound device will work only on specific site and player

Hello out there,
Well, I have a desktop computer with a Gigabyte motherboard with integrated sound card, Intel pentium 4 (3.0 GHz), 512 Ram.
Operating system is Windows XP and the sound card driver had to be found. I had the hardware details from the Device Manager list; right click on the uninstalled hardware, the one with a yellow background exclamation mark on the left of it, get to the hardware properties details and copy the Hardware ID. It read : PCIVEN_8086&DEV_24D5&SUBSYS_A0021458&REV_023&13C0B0C5&0&FD
I pasted that on www.google.com and followed a link to get the hardware driver. Though nearly half the characters from the ID above had to be reduced for Google to return and answer.
Finally with the correct Realtek AC'97 Audio driver, I get a sound output.
My constraint is that when I am on youtube, streaming audio, there are times when the sound goes out with the video going on and after intervals, I get the sound back. Note that the video has already been streamed completely. In fact everywhere I stream audio alone or along with video, the sound output is irregular.
I have the similar problem even when I am viewing an *.mp4 movie on GOM player. Sound goes off and on.
But the problem is kind of solved when I play on VLC media player.
I do not think my computer is too slow because I can run many applications including webpages at the same time without a real slowing of the computer speed.
I might think I got the wrong driver, but I had this one described from many sites as the best match for my hardware ID.
If anyone can advise, please help.
