svchost.exe is a perfectly normal windows executable. It's responsible for most of your services such as computer browser, RPC (remote procedure call), windows themes etc. You can attempt to task>kill svchost.exe but you'll almost instantaneously be hit with limited performance implications. And typically, svchost.exe may have as many as 5-6 instances depending on the number of services you've enabled.
If you want to disable unnecessary services from running then go to start>run, type services.msc and press enter. In the list of services, select which ones are necessary and which ones aren't. However, if you don't have a general idea about this, then I suggest that you don't mess around.