Chabgung?
A bit tricky, but not impossible.
You could :
1. Boot from a Live CD.
2. Mount your install partition(s).
3. Back up everything into a tar archive ( Preserve permissions! ).
4. Format install partition with a different filesystem ( ext3? ).
5. Restore from tar archive.
Some loooong guide below, some of which I don't agree with, but a good starting point :
http://duopetalflower.blogspot.com/2010/01/how-to-migrate-ext4-partitions-to-ext3.html
Is this a different issue to the filesystem and also the instability problem?
Heh ok You've not taken in a word of what I've said have you you'll be able to check the hardware on your system with lspci, lsusb, dmesg, Ubuntu might even have a hardware listy thing in one of the menus. GL Ed!