Hiya! Here's some tips:
1 - It IS OK to use Gparted to resize partitions, including NTFS ones.
2 - it is NOT RECOMMENDED
to relocate the START
of a partition. Generally the way to resize is by stretching the partition by extending the END
of it further.
3 - It is ADVISABLE
to use Gparted from a LIVE-CD
if you will be doing operations on the same hard-drive and/or partition from which you are currently running your system. Definitely not a good idea to operate on a mounted partition, if it will even let you.
4 - It is VERY ADVISABLE
to defragment windows/NTFS partitions before attempting to do partition-adjusting operations on them.
5 - Adjusting partitions is never 100% guaranteed to be successful, but if you follow these general guidelines, you give yourself the best chance of 100% success.
Best of luck!