1998 isn't that old, and the bike should still be able to compete against a current bike; and if it's a road bike you want why ,are you looking to get rid on the drops (take it this what you mean by curve bars?), as this virtually defines what a road bike is.

For the amount of work you are proposing, it would probably be easier and cheaper to buy a complete flat bar bike. For what you are planning, would list everything you currently have, so you can work out what you want to change, and what to, and replace with, then work out what it will cost. For if parts will fit, that's easy, as it, the measurement / specs have to match, for it being proper, nothing will be proper if you are taking off the drops, and intending it to still be a road bike.