|You may have a virus, malware infection, overheating CPU, too many programs loading & running in the background, not enough RAM, etc, etc. You haven't provided enough info for anyone to help you to pinpoint the problem.|
Start by running CCleaner, either the portable version or CCleaner-Slim. Run the Cleaner & remove everything it finds, then Scan for Registry Issues & fix all that it finds.
After than click Tools > Startup & have a look at the startup list. Are there dozens of entries? You probably only need a couple of them.