Under the Performance Tab do you see a Wi-Fi Throughput? That's if you use Wireless in the first place.
In the Control Panel\All Control Panel Items\Network and Sharing Center\View your active networks\connections, if you click on your Network is there any activity shown there in the Status page?
Before you change anything backup your valuable data and make sure you can reverse your steps.
How to create a system image to refresh your Windows 8 PC
http://support.microsoft.com/kb/2748351
How to create a custom refresh image in Windows 8
http://www.bleepingcomputer.com/tutorials/create-custom-refresh-image-in-windows-8/
Maybe you have some third party Imaging software to use.
When you create the new Windows 8.1 it must be only on this current computer, you cannot run the same Product Key on multiple machines unless you are using Volume Licensing.
You will just boot from your DVD, or USB, and use the Setup to create or delete partitions prior to installing Windows. You probably will need to visit Lenovo for drivers after installation.
Clean Install of Windows 8.1 on ThinkPad and Lenovo B, E, K, M, and V Series Notebook Computers - General
http://download.lenovo.com/lenovo/content/windows8-1/upgrade/think/notebook4_en.html
https://www.google.com.au/search?q=clean+install+windows+8.1&sourceid=ie7&rls=com.microsoft:en-AU:IE-Address&ie=&oe=&gfe_rd=cr&ei=VYNQVIafJ8uN8Qer5IHgBg&gws_rd=ssl