The answer to that depends entirely on whether you saved custom files in other locations, or not. If you let ACADE decide where to save things, then you might be OK. But, this effort needs to rope in more than just your custom symbols.
If you have made any changes to the icon menu itself, you'll need to copy those files over. This includes changes like altering the structure, adding icons, etc. If you've made any edits to the catalogs, the catalog files need to be copied over as well.
Where is your title block stored? Your templates? Those files will need to be included in all this.
What about plot settings? Ever edit your ctb or stb file? If so, those too will need to be copied. Lump the .pc3 files in with that too.
In reality, your best bet is to have your IT folks make a disc image of your current computer, and then bring all of that over to the new one after it's set up. If that option exists for you, my advice is to do it that way. Barring that, the next best thing is to make sure that the old computer is available to you for a while - say, a couple or three weeks. This will give you enough time to discover anything you might have missed.

Jim Seefeldt
Electrical Engineering Technician