The problem is well know, its caused by a sept 2013 windows update. Its causing to chcek for update file, and each +1 update costs 2times more to check than a previous one. It can make your PC use cpu for 100% for hours..
Actually there are a few solutions.
1. Turn off windows update.
2. Download a windows XP install that has the latest update included, you can find many images around the web. I personally dont recommend black edition xp, the best is the clean verion.
3. Let the PC finish updates. It can mean that your pc will run on 100% for a few hours, but after that the problem should be gone, until the next update.
4. Get windows 7, it can run ok with 1gb memory, but if you have 2gb I definitely recommend win7 over XP.
I dont recommend killing svchost.exe at any time. This is a core system process and shutting down means that your system will not function properly. Also by regular process killing you can damage the system, which will cause you to reinstall the pc again