Backend slow on some computers

I’m new to wordpress, so I hope someone can help me; I have a site that was just installed. On my work computer the backend (admin panel) works perfectly, and I had a few other people test it out and it worked great.
However, on my home computers (laptop and desktop, both with wireless network cards), the backend is unbelievably slow to the point where it just doesn’t work (I’m trying to get the version #, but can’t even get it to load).
I tried it on Firefox, Chrome and IE, on both computers and it’s the same problem.
Hopefully someone can give me a suggestion how to fix this issue.
Thanks!