I've had this happen to me before, Answer a few questions for me and I may be able to help you,
1. What Version of Windows Are You Running (XP) (Vista) (Windows 7)
2. Are You Using any Hacks
3. If you are using Hacks, Make sure to run them As Administrator
4. How much Internet usage do you have left (Ask yourself that question)
5. Do you have a Virus on your Computer
6. Have you modified Combat Arms to any extent