keep getting error sound when trying to connect to computer

[omarh3]

Im running viper xl 2.1.0 and now when i try to connect my phone to the pc i just get an error sound and it wont connect. Is there any way to fix this, i cant flash any roms because of s-on without fastboot comands and i cant transfer files back and fourth between phone and pc. Please help, if anyone out there knows how to correct my problem please give me the instructions to fix it. Thanks and HELP!!!!!