HP Media Center PC won't boot

My 8-month old HP Media Center PC (HP Pavilion m7690y), running XP Media
Center edition SP2, refuses to boot. It's run fine through yesterday and
shut down normally last night.

This morning when I pushed the power button, I got a repeating audible
signal: 1-short 1-long single tone, and the card reader active light was
on although nothing was in any of the slots. Not even the pre-boot on-
screen messages (F1, POST, Setup, etc.) showed, the machine was hung
there,and there appeared to be no hard disk activity. Nonetheless, it
continues to pass my internet connection to my wireless router.

Anybody got any ideas.

TIA

noend7
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