Weird XP cursor help

This is the first time in my life I’ve ever come across this in my computer life. This is what it is. The cursor is the old style, DOS type blinking square cursor, when I hilite something to type over it, it will not write over the last character. Pressing insert does not change it at all.

The system is WinXP HE (OEM) upgraded from Win98.

Help please?

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