Thanks SuperSparks, I downloaded the HWMonitor (no installation) and ran in the computer, it only gives me the HD temp. I ran the same in my laptop, it gave me CPU, GPU and HD temperatures.

Now I notice the long beep happens when the computer freezes and I repeatedly clicks the mouse or press the keyboard many times. If I hold the on/off button to shut down the computer and immediately turn it on again, the computer runs and freezes again after sitting for a while even though no application is manually opened.

I ran hard drive test by SeaTools - all tests passed and temp of HD is about 39C. I have tried to disconnect the CD rewritter, floppy drive, took away the added video card (use the o/b video) - all attempts eventually had frozen computer. I did run Spybot, found about 30 cookies and 1 unwanted program - Generic PUP.Z!cg, I removed it. Ran the McAfee Internet Security, found Fraud.Sysguard, I removed it. Still the computer freezes. The McAfee loaded on booting up, it prompts the computer is not fully protected. 2 buttons: Check Protection Status and Close are display on the message box. I click the Check Status and verify 3 subscriptions: Personal Firewall, Parental Control, Anti-spam; all verified (the subscription expires in 2011). Next booting up, this message pops up again. In some occasions, I also click Close. In both scenarios, the machine froze in a few minutes.

Now, I leave the above message box sitting there and take no action. It runs almost an hour without freezing. I have opened the Task Mgr, Excel, FireFox and jumping among them and also surf on the Internet.

I have run the HJT and will upload the log in the next post. Thanks.