Post contents of..
/etc/X11/xorg.conf
/etc/fstab
..although I'm 99% sure that mint (like ubuntu) uses UUID's so there should be no issue with the fstab.
What graphics chipset are you going from and to and have you installed any additional graphics drivers?
NVIDIA GeForce 8800 GTS to NVIDIA GeForce GT440, unless Mint did it on its own at install, no drivers are installed.
fstab
# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc nodev,noexec,nosuid 0 0
# / was on /dev/sda5 during installation
UUID=f733b732-d7d7-410c-ad19-df2c18a4fa81 / ext4 errors=remount-ro 0 1
# swap was on /dev/sda6 during installation
UUID=0e05a4c1-e898-422e-9e02-6dae7eb78e7c none swap sw 0 0
/dev/fd0 /media/floppy0 auto rw,user,noauto,exec,utf8 0 0
I posted a pick in the above post, no xorg.conf file.