Why is my computer running so slow?

Get some antivirus software on your computer then update the antivirus software and run a complete system scan on your computer.You might want to press Ctrl+Alt+Delete to start the task manager and see what processes are running on your computer. If you see one of the non essential processes taking up all of the memory and/or all of the CPU, you might try right clicking on the offending process and select "end process tree" to see if that speeds up your machine. Defragmenting your hard disk can speed up your machine a little.