Copied items appear in the clipboard for 5 seconds and then disappears

[AWS]

PC running winXP SP3. I've tried scanning the computer for viruses and malware using a variety of softwares. When I copy an item (ctrl-c), the item stays in the clipboard for about 5 seconds and then disappears. I can paste the item within the 5 seconds,
but after that, there is nothing to paste.

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