I am facing what appears to be a malware, my browsing is slow, my browser hangs and also my system has become slow

Question

I am facing what appears to be a malware, my browsing is slow, my browser hangs and also my system has become slow, these are symptoms, I cant watch videos on youtube

Answer 1

You installed the "DownLite" trojan, perhaps under a different name. Remove it as follows.
Back up all data.
Triple-click anywhere in the line below on this page to select it:
/Library/Application Support/VSearch
Right-click or control-click the line and select
Services ▹ Reveal in Finder (or just Reveal)
from the contextual menu.* A folder should open with an item named "VSearch" selected. Drag the selected item to the Trash. You may be prompted for your administrator login password.
Repeat with each of these lines:
/Library/LaunchAgents/com.vsearch.agent.plist
/Library/LaunchDaemons/com.vsearch.daemon.plist
/Library/LaunchDaemons/com.vsearch.helper.plist
/Library/LaunchDaemons/Jack.plist
/Library/PrivilegedHelperTools/Jack
/System/Library/Frameworks/VSearch.framework
After moving all the files, restart the computer and empty the Trash.
From the Safari menu bar, select
Safari ▹ Preferences... ▹ Extensions
Uninstall any extensions you don't know you need, including any that have the word "Spigot" in the description. If in doubt, uninstall all extensions. Do the equivalent for the Firefox and Chrome browsers, if you use either of those.
This unwanted program is distributed on illegal websites that traffic in pirated movies. If you, or anyone else who uses the computer, visit such sites and follow prompts to install software, you can expect much worse to happen in the future.
*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination  command-C. In the Finder, select
Go ▹ Go to Folder...
from the menu bar, paste into the box that opens (command-V). You won't see what you pasted because a line break is included. Press return.