Can't login on my PC

[Moderator note: Please don’t uppercase your sentences]

I have taken over a WP site. When I first started using it, I was able to login on my laptop. Now I can’t. I don’t get an any error message. The Login button indicates that it is being selected, but nothing happens. Looking through old forums, this seems to have been a problem for many years.
I’ve tried clearing cookies. I’ve enabled popups on this site. No luck. I’m using Windows 8.
I am desperate. I need to work on this site ONLY from my laptop, and it’s URGENT! Please help.
Please keep lingo simple – not a programmer or web developer.
Thanks.