Sure, you can try that, I have NOT done it myself. If that work, you can do the following to format the microSD in the N810, provide that the N810 recognize the existence of the SD card. If not, you back to your XP box.

If the card is recognized in your N810
1) File manager, format the card

2) xterm
sudo gainroot
umount /media/mmc1
mkdosfs /dev/mmcblk1p1
reboot

You may have to install e2fsprogs, some useful info here,

And if xterm/format does not work, I would repartition the whole card. And watchout for this bug if you choose to do that, a bug that reads beyond the physical limit of your card...I am looking it up now.... got it thread #71 and #72.
good luck,

bun