You can stay safe by using on the "Startup" tab in "msconfig".
As Adamness indicated, steering clear of the other tabs might be best without prior knowledge or competent instruction.
To enter the System Configuration Utility (msconfig), go to "Start > Run > type: msconfig > press "Enter".
When the System Configuration Utility dialog displays, you can safely click the "Startup" tab, and you will see many of the "programs" that run at startup. This is not a comprehensive list, but disabling these can be done and undone without major issues, other than the perhaps a program not working correctly.
Note - some of these processes probably belong to your Anti-Virus, and perhaps Firewall programs, so be wary of what you disable.
If a problem occurs, reenter msconfig, and click the "Normal Startup" option on the General tab > click Apply > OK > Restart computer.