You shouldn't experience any problems, difficulties usually come up when you try and install for instance windows XP on a system designed for windows 98 and such, does that make sense?
Anyway, don't take my word for it but you should be just fine.
Like what exactly R53's. I want to know everything you mean. Because I'd like to try new software but I'm perfectly happy with win 98 and I would just as quickly install that onto the new pc just to free up the Ram.