Problems with a subdomain–cannot access

From what I’ve seen around the forum, this may sound like “oh, no, here we go again!”…but…

Recently I had www.remarpro.com (version 2.9.2, NOT 3.0) installed for me on a friend’s domain, also Joomla and Coppermine. I was working in there and all seemed peachy until one day, a draft started to “hang” and I had to shut ‘er down for awhile. When I came back, I could no longer log in. Anywhere. At all. My pal suggested maybe I had the wrong URL, which wasn’t really possible since I bookmarked each login index and how could I mess that up…? Then she said the link was gone (felt maybe the theme I used was at fault). Today she said everything works perfectly on her end. But “the link is gone.” So…duh…? Now she’s asking about which browser I’ve been using to try to get in, but I wouldn’t think that would matter? I only have IE8 and Firefox.

She’s going “You’re a big girl, you can do this, search harder for the answer. Can’t fix what ain’t broken.” But I’m not that knowledgeable, and even if I was, this is totally mystifying! I have no clue what to try next to get back in. It’s so frustrating when my pal finds no problem and thinks the trouble is on my end. But what could possibly be causing me not to be able to log in at all? Why would a link just vanish?

Anyone else ever have this kind of problem? After almost 2 weeks I still can’t log in at my own WP!

Also, I do not have any extra plugins included on my site. It’s quite a simple and basic site and I haven’t even thought about using them, yet.