I think it can be a bit tricky swapping a mobo because the existing OS installation has all the drivers for the old one. I've buillt a two PC but I've not had to do a mobo swap yet.  Might be worth googling to see if there is anything you should do to prepare the old installation before the swap - that's assuming you don't want to reformat and re-install everything. If that's not important do a clean install.

I'm very out of date re mobo's.

If you are sure the caps are leaking..  have you considered trying to replace them?  My understanding is that it's the big electrolytics that have the problem so there shouldn't be too many. Probably worth replacing them all while you are at it.