I have built a new system. I get a random BSOD in ndis.sys:
What is ndis.sys used for ?
Is your error code 0x00000D1? If it is that means a faulty driver or buggy software is the culprit but we don't have nearly enough information to help. ndis.sys is a core Windows OS driver but that is too general to lend help.
If you can, attach some minidumps in your next post.