[Newbie]server resolution

[vnis form parsing mailbot]

Hello ... here's a new one to me .. I installed xfree86 4.2.40 on my linuxbox ... after running xf86config numerous times and run startx i end up with a screen resolution of 320x200 with very large fonts and only half a screen of usuable area ...  I have tried to 'force' a resolution of 640x400 to no avail ... also, while in the server I cannot ctrl-alt-+ to switch resolutions .... besides trying to find another video card for this old system .. what can I try doing??   Thanks in advance, Gregg