im trying to shrink a partiton on my c drive exactly the same way as ive just done on a vista laptop , but when i go in2 computer management then try to shrink volume i put in 30000 but at the bottom the shrink button stays greyed out no matter what number i put in
please help i need to dual boot
please help i need to dual boot

My Computer
- OS
- 7 RTM 64bit
- CPU
- AMD Phenom 965 B3
- Motherboard
- ASUS M3A79-T DELUXE
- Memory
- Corsair 4GB (2x2GB) DDR2 800MHz/PC2-6400 XMS2 Memory Kit CL5
- Graphics Card(s)
- PowerColour HD 5770 CF 16x-16x
- Monitor(s) Displays
- 32"
- Screen Resolution
- 1920-1080
- Hard Drives
- Hitachi
1tb 7200rpm
- PSU
- Be Quiet Straight Power 650wat
- Case
- Asus TA-M series
- Cooling
- CoolIT Eco ALC Water Cooling System
- Keyboard
- Microsoft wireless Keyboard
- Mouse
- Microsoft wireless mouse