Cause 1: Too Many Startup Programs
When too many programs start with Windows, your computer takes minutes to become usable. Open Task Manager (Ctrl+Shift+Esc) > Startup tab and disable any programs you don't need immediately at login. Common culprits: OneDrive, Dropbox, Spotify, and browser update helpers. This is a free fix that takes 5 minutes and can dramatically reduce startup time.
Cause 2: Failing or Old Hard Drive
Traditional hard disk drives (HDDs) slow down as they age, when they're nearly full, or when they begin to fail. If your computer is over 5 years old and still running an HDD, an SSD upgrade is typically the single most impactful improvement available. Boot times drop from 90 seconds to under 15 seconds. Use our SSD upgrade check to see the estimated benefit for your setup.
Cause 3: Insufficient RAM
Running out of RAM causes Windows to use your hard drive as temporary memory — which is dramatically slower. 4GB of RAM is insufficient for modern use; 8GB is the practical minimum. RAM upgrades are possible on most desktop PCs and older laptops.
Cause 4: Malware or Virus Infection
Many types of malware run silently in the background, consuming CPU and RAM resources. If your antivirus software is disabled or expired, run a scan with Malwarebytes as a first step. See our guide to virus symptoms for other indicators.
Cause 5: Overheating
When a CPU runs too hot, it automatically throttles its performance to protect itself. This causes sudden slowdowns, especially under load. Use our overheating check to diagnose this — and book a professional clean if your laptop is running hot.
Cause 6: Full Storage
Windows needs approximately 15–20% of your drive free to run efficiently. If your C: drive is over 85% full, start by deleting files from Downloads and emptying the Recycle Bin. For a more thorough cleanup, use Windows Storage Sense (Settings > System > Storage).
