I really don't think these procedures have changed much recently. Uninstall unneeded programs from your computer Run a virus scan Run a malware scan Make sure the computer is up to date Install more system memory Install an SSD if you haven't already Verify the fans work and the system is free from dust Re-install your operating system If you're comfortable re-apply thermal paste on the processor  
What are your best tips for fixing a slow system? For more questions regarding this contest, please visit the Information Page here.
DS 07/23: What are your best tips for fixing a slow system?