From what I've read of svchost, it can be called upon to run several services and you can find these using task manager (ctrl-alt-del). You can also look at performance and a slow PC often means something is occupying too many cpu cycles. You can try shutting off processes one at a time and rechecking the performance tab to see what what drops your cpu usage. If you find a specific service that, when stopped, causes a significant drop in cpu usage, you might investigate to see what that service is used for and how necessary it is. Check here

Your options could be to either set it to manual if it runs automatically or disable it if it seems of no use. You can always re-enable it if you find some function not working. Good luck.