partitioning hdd in dell inspiron 15R

i have recently bought a dell inspiron 15R laptop in which an OEM partition(125mb), a recovery partition(9.5gb) and a c: partition of 288gb is present. I'm trying to create c drive of around 50gb and another drive of the rest of space(238gb) by using 'shrink volume' option..but shrink size beyond 145gb isn't allowed so I can not create c drive of less than 145gb which I don't want to. Is there any way to make c drive of less than 145gb(say intende 50gb)? please help me. thanx in advance.....

Use free Partition Wizard bootable CD to "Resize" C. Partition Wizard.URL

If you still can't shrink enough, then defrag using Auslogics Disk Defragger to see what files are blocking shrinkage on the right side.

If these are System Files, use free Perfect Disk 10 trial program to first "Shrink to consolidate files", then rightclick C to Offline Defrag>System files.

Gparted.