I have done it with good success, but the computer was all cleaned up and sitting on my bench. It takes a while to do and you have to think it thru before you start, so you get everything to come out correctly. You have to be careful to not put too much pressure on the vinyl strips, or the numbers will be out of alignment.
Its not a simple task and if you haven't messed with computers quite a bit, it can prove difficult. One good thing-- if it doesn't work out for you, you're not out a lot of money, because the decals don't cost a lot, and maybe the second time will be a charm! Good luck!