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What would cause my PC speaker to sound a low frequency continuous tone as my system locks up? Generally what will happen is I'll notice the application I'm using will stop responding but explorer will be partially responsive, then after a few more actions explorer stops responding, and the last click will cause the pc speaker to emit a low constant tone as the machine locks up completely. The only resolve at that point is to restart.

Its not a thermal issue, I'm reading the cpu, and hdd temps with software and hardware monitors. AV and malware scans come up clean. I've swapped out my ram, reseated all my components. Used sfc with no results. chkdisk locks up at 3% and defragmenting does the same, but I can read the drive without trouble (I know this as I've done av/malware scans and I also backed everything up since this started happening) I'm mostly just interested to learn, if anyone knows, why the pc speaker would sound during the lock up.

windows xp sp2

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A wild guess but may be the beginning of the windows error message bonk noise? Good to hear you backed everything up. I would be expecting a hard drive failure fairly soon.

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When this has happened to me it's always when I'm listening to music. I have no facts to back this up, but my half-baked theory of the day is that at the moment of the crash, the computer is sending output to the speakers - channels open, interfaces enabled and signal is flowing. After the crash, the signal pathways are still open, but the computer is no longer sending any signal. The sound that ends up coming out is some combination of whatever oscillations are available - could be 60Hz or a harmonic.

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I've discovered this exact same issue. However, I've discovered it on three different computers all protected with a program called Deep Freeze, which prevents users (patrons in public libraries) from making any changes to the computers. On one computer, the machine was "frozen" for approximately 2 weeks before the exact symptoms you described started. On another computer (at an entirely different library), it was about 4 weeks, with the third about 5-6 weeks. With Deep Freeze, NO changes will stick, so I am positive that software hadn't been added/changed. The workstations were working fine until the symptoms showed up, after which time the symptoms became permanent in spite of Deep Freeze. Using various methods, I was able to confirm that the hardware on all of the workstations was NOT the cause. The only resolution was to re-image the workstation hard drives from identical computers. So far, I have no cause other than to say that the updates that were done on the workstations the last time they were "thawed" included: Microsoft Updates (my prime suspect), Adobe Reader update to v9.3.1, and a smattering of other lesser program updates unlikely to be the cause. If anyone else has this issue, I hope these observations help.

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