Well, to be able to help you - understanding the exact problem you are having would be our first step.
1. What errors or issues are you having when you attempt to access Cpanel?
2. Have you tried clearing cookies, temp files, junk files ( using Ccleaner is good ), flushing you DNS and rebooting your computer? ( All this should be done, not just 1 or two ... if you have done one or two, try stopping - doing each option then trying again before saying nothing works still )
3. What is your Cpanel name and you website URL?