So, here's what happened:
I had my proofs from my photo shoot on a disk. Well, I had the disk in my computer. Long story short, computer broke. Had to replace. Now, disk is gone. I could really use it on my website right now. Is it fair to ask the photographer? Should I expect to be charged?
Thanks!!

I would ask and expect to be charged.

No harm in asking but there may be a charge. Many don't though.

Photographer might not have them either. Shoots take up a lot of hard drive space if the photographer has the right equipment and is shooting a decent file size.

most photogs keep them on drive for atleast a year...
In my experience atleast.

Its totally fine to ask the photographer - but do expect to be charged. Depends upon the photographer of course, and your working relationship with them - I've got repeat clients who can ask for just about anything and get it.
As hollywoodmodelphotography mentions, be prepared for the photographer to maybe not have the photos anymore - particularly if its been a while. I dispose of delivered shoots pretty regularly.

By all means ask the photographer. I keep ALL my files for reasons like yours.

Maybe if you offer the photographer a disk and or a cup of coffee they'll take a minute out of their day. Good Luck!