Neither will run it - sorry ....
They use integrated graphics chips - "on board" graphics, and the game does not support those.
Game hardware specs:
http://www.2kgames.com/civ4/support_msr.htm
Your Dell PC has a PCI bus with no AGP port, so upgrading to a card is not an option there either. Your PC specs are:
http://support.dell.com/support/edocs/systems/dim2400/en/sm_en/specs.htm
Its a PC/Laptop upgrade to run it I'm afraid...
Re Civ problems - its certainly true there were a number of problems around, patch V1.52 solved many. The initial release was driven by the commercial side of life with the Xmas market in mind, dont mix that up with the Firaxis programmers ability. The latter are good, they had a commercial deadline to meet initially - thats a commercial decision not theirs - when they had the chance V1.52 came along. I anticipate the stability & features will improve markedly over the mext couple of months / as the year goes by. Dont be too swayed by negative posts, in the region of 6m copies went out, and you will only hear of those with problems, the rest dont bother to say "its ok".
At present the majority of problems post V1.52 are those with hardware not meeting the game requirements, such as yours that you are wisely checking first before buying ....
Of course you may hit issues, and its frustrating (been there

) but thats no more so than other games - particularly in the earlier releases.
Regards
Zy