Many "free" tools include Remote Access Trojans (RATs) that allow attackers to control your computer, access your webcam, and monitor your keystrokes.
"Multi Checkers" are automated scripts or programs designed to test large lists of usernames and passwords against various websites to see which accounts are active. Download Multi Checker Link1337 zip
If you must run unknown software, use a dedicated, isolated environment like Cuckoo Sandbox or a virtual machine with no access to your personal files or network. Many "free" tools include Remote Access Trojans (RATs)
Check your system for suspicious background processes (e.g., proxy.exe , tun2socks.exe ) or unauthorized tasks in the Windows Task Scheduler . access your webcam