I'm surprised that Excel 2013 doesn't respond to <Ctrl-K>. I'm also a little distressed, because I use that option often and I'd hate to do without it if and when I graduate to Office 2013.

However, let's explore a few hypotheses:

1) You're mistaken—you just hit the wrong key. That's the most attractive hypothesis but it's not likely, and anyway there's no way for me to test it from here :-). Ok, next:

2) Excel 2013 still has the capability, it just changed the keystroke. I kind of doubt this one, but let's see. If you go to the Excel ribbon and select Insert, you'll see just a little short of 43 jillion things Excel will let you insert. About a third of the way in from the right end is "Hyperlink", and if you mouseover that option without clicking, Excel displays "Insert Hyperlink (Ctrl+K)". Rather, that's what it displays on my machine; what on yours? Maybe it displays a different keystroke, and Bob's your uncle, there's the answer.

3) Excel 2013 doesn't have a customize-ribbon option? That's odd; it's a pretty fundamental part of Office products. In my version (2010) I get to it by hitting <Alt-F>,T and I see it down the left masthead-looking thingy. What do you see?

4) If you really don't have Customize Ribbon (and I'm incredulous about that), how about customizing the Quick-Access Toolbar? That, too, is in the options.

5) Failing all that, maybe you can write a macro and tell Excel to run it whenever you hit <Ctrl-K> (or any keystroke of your choice?

You know, I can't get past you saying you can't do Customize Ribbon. Is this perhaps a PC you use at work, and the nasty ignorant suspicious security types have decreed that it's something ordinary users aren't allowed to fool with? As a contractor I run across this sort of thing frequently: not allowed to set my keyboard to Dvorak, not allowed to change my regional settings to ANSI-standard date format, not allowed to move my task bar to the left, almost anything might fall prey to a fearful policymaker who hasn't thought things through. If so, experience leads me to suggest that you can probably get an exemption.