New Install Of XP freezes for 10-15 Seconds?

Installed XP home ed on a new WD 500gb Sata drive. Went to my mother's house for Christmas and soon after, the boot sector became corrupted and it wouldn't boot into windows. Used an older hard drive until I could get back home to the install disc.

In recovery concole, I was able to do a partial chkdsk /r command. I was able to retrieve some needed info such as email addresses. Did a quick format on it and installed XP and the updates.

Almost like it's on a cycle, the computer will freeze up except for the mouse for 10 to 15 seconds about every 90 seconds. Press the start button with the mouse and it may not open for 5 seconds. Or, it may open immediately.

This happens with all programs that I'm aware of, not sure if it locks up when watching a youtube video. When typing a message in yahoo messenger, text will not appear but it appears that the information isn't lost as at the end of the freeze, what I typed will appear and I can send the message.

This is a desktop, 2. gig AMD Athlon 64 X2 dual core with 2 gig of ram. I checked the system hardware and no ! or ? marks with the video display.

I reinstalled XP on the old hard drive without reformating it and I don't have any problems other than it's a bit slower than it should be. I assume that not being formatted some of the system files are fragmented.

Using the older hard drive that I installed a workable copy of XP, I ran the antivirus and spybot. Also ran chkdsk for bad sectors. Nothing came up on the new drive, though the older drive had some bad sectors but none on the Windows folders.

Ran set up again on the new drive. This time I deleted all the partitions and did a quick format. The only things I installed were the main drivers for the video and sound and the firewall. Kept it unpluged from the net but the same thing, freezes up for about 10 seconds at a time except for the mouse.

What's going on?