I think windows must have changed something on disk, to confirm this, first grab the first 63 sector in Linux:
sudo dd if=/dev/sda of=mbr_1 bs=512 count=63
Boot to windows, then boot to live cd. Then, grab the sectors again:
sudo dd if=/dev/sda of=mbr_2 bs=512 count=63
Compare the files using cmp: cmp mbr_1 mbr_2
I think windows must have changed something on disk, to confirm this, first grab the first 63 sector in Linux:
sudo dd if=/dev/sda of=mbr_1 bs=512 count=63
Boot to windows, then boot to live cd. Then, grab the sectors again:
sudo dd if=/dev/sda of=mbr_2 bs=512 count=63
Compare the files using cmp:
cmp mbr_1 mbr_2