Hello Kum, welcome to Seven Forums!
Have a look at this tutorial at the first link below, use only Step One
to Move/Resize the left side of the J: partition to create unallocated space, when the Resize is complete close the Partition Wizard program and re-start the PC and use Windows 7 disk management to extend
the C: partition into the new created unallocated space.
System Reserved : Create for Dual Boot
First download the Partition Wizard Bootable Disk (PWBD) ISO file to the desktop, be sure to get the PWBD and not the installed version; scroll down to see the download link for the bootable CD ISO file at this link below.
Partition Wizard Free Bootable CD
Then use ImgBurn to burn the ISO to a CD, at no greater than 4x speed with a verify; it was designed for use and works best from a CD rather that a then boot
the created CD to make the changes.
ImgBurn Free ISO Burning Software
Be sure to post back with any further questions you may have and to keep us informed.