Why is my tp-link going in and out connection

[fleecie]

I have a tp-link 725N 150 mbps on an old IBM Netvista and its upstairs and my Bell 2 Wire all in one Router is Downstairs.
When I turn on the computer upstairs the connection goes in and out.
What can I do to correct this problem.

 

[supervai]

is the signal not consistent or weak?