When i open and have a program running should the cpu usage be 100%? In my case 50% coz of htt.

Im not sure if i undestand your question correct but if you mean that when ollydbg is open and you open a other program that then the cpu usage goes to 50% (100%) then its maybe an ollydbg protection.

When the debugged program is running under olly im just wondering if the cpu usage should be 100%?