If it is one long beep, that means the RAM has problem. To clear the CMOS by removing the battery or other way http://pcsupport.about.com/od/fixtheproblem/tp/clearcmos.htm and only use one stick RAM if you have more one. And try boot the PC again, also if you can boot the PC, try use the "memtest86+" to test the RAM. http://www.memtest.org/