Don't know if this thread will help:
http://talk.maemo.org/showthread.php?p=614293
and I assume you have read the Wiki
http://wiki.maemo.org/Updating_the_tablet_firmware

Windows 7 has caused problems for others, but as it has worked in the past for you it should work again.

Does your PC make the USB correction sound when the phone gets plugged in and another sound when you unplug it. If not reinstall PCSuite.

You could try taking the battery out for a few seconds, then reinsert it, with out switching it on hold down the U key and plug in the usb cable. Does the USB symbol appear on the screen, if it does run the flasher with (as ToJa92 said) the FIASCIO image first then the eMMC without switching it on inbetween the two flashes. Backup your data first.