It would help if you tell us the brand and model of your case
If you can't figure it out, you should have in the back of your case a 120mm fan mount, probably occupied already. This could be the only place you could fit your cooler. You probably want to check for spacing before you buy your new cooler.
Check the specs of the cooler and measure your case clearance: http://www.corsair.com/en/hydro-series- ... m_store=pt
Intel i5 3570K @ 4.3 GHz, Corsair A50 (Be Quiet Fan), Asus P8Z77-V, Corsair 2x4Gb @ 1333 MHz CL9, Asus 280X Direct CU2 @ 1150/6800 MHz, 2x Corsair F90 RAID 0, Samsung Spinpoint F3 1Tb, Antec One Hundred, Corsair CS750M, ASUS MX239H AH-IPS, Win 8.1 N Pro