What kind of hash is it? Cain & Abel can crack the following types of hashes:

LM
NTLM
NTLMv2
MS-Cache
PWL Files
Cisco IOS-MD5
Cisco PIX-MD5
APOP-MD5
CRAM-MD5
OSPF-MD5
RIPv2-MD5
VRRP-HMAC
VNC-3DES
MD2
MD4
MD5
SHA-1
SHA-2
RIPEMD-160
Kerb5 PreAuth
Radius Pre Shared-Key
ISE-PSK
MSSQL
MySQL
Oracle
Oracle TNS
SIP
802.11
WPA-PSK
WPA-PSK Auth
CHAP

which one of those (If any of those) do you want to crack or decrypt, NetTools by Relix has a very good file Decrypter...

Cain & Abel can even use Cryptanalysis Attack on some of those mentioned hashes, Brute Force on all. You can get Cain & Abel here: http://www.oxid.it and it has a help file that tells you step by step how to use the software.