Yea, you will be able to run it but you won't be able to play it (Probably not even at minimum settings and minimum resolution... it will just be really really slow!). Every single game's minimum specs are the specs you need to have for the game to install and then run... it doesn't mean that you will be able to play it. In fact with those specs you will have trouble even playing FS2004 decently (by that I mean having most things maxed and getting good fps).
You should definitely consider upgrading your cpu to a better one, getting more RAM (at least 2GB) and a new graphics card. If you can't upgrade, just don't even buy FSX because you won't be able to play it decently... if you do manage to play it, it will look worse than FS98.
Hope I was able to help you... cheers
