this happens when your disks are not mounted automatically when system starts, to mount automatically:
first of all, get the UUIDs of your disks: open a terminal, type 'ls -l /dev/disk/by-uuid'
now you see the information of all disks.
then type 'sudo gedit /etc/fstab'
in this file, add lines like below in the end, mine is: (the last 4 lines are added)
# /etc/fstab: static file system information.
# Use 'vol_id --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 defaults 0 0
# / was on /dev/sda8 during installation
UUID=5df12082-5551-42f2-9e2f-3849c46706dc / ext3 relatime,errors=remount-ro,acl 0 1
# swap was on /dev/sda9 during installation
UUID=801505bf-459c-4e6d-acbd-0db958827723 none swap sw 0 0
/dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0
UUID=F644E46844E42CD5 /windows/sda1 ntfs auto,user,nls=utf8,umask=0 0 0
UUID=15636A6A99858A81 /windows/sda5 ntfs auto,user,nls=utf8,umask=0 0 0
UUID=FAE040DEE040A2AD /windows/sda6 ntfs auto,user,nls=utf8,umask=0 0 0
UUID=4B20B8DF297FB783 /windows/sda7 ntfs auto,user,nls=utf8,umask=0 0 0
just replace the UUIDs above with yours, you may or may not need to create files '/windows/sd1,5,6,7' (whatever the names are), then type 'mount -a' in terminal to remount, if everything goes well, you should be able to see the files /windows/sd* and in them is your staff in Windows. then your disks will be automatically mounted when ubuntu starts, you won't need to reload the lists again and again.
hope helped and good luck!