Depending on the version you are using, I would recommend a file gdb over a personal GDB...you will most likely have fewer issue down the line, especially if you start reaching the limits of Access.
I had written these instructions up a couple days ago for another thread...I'll include them here.
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ake a look at this help topic Make XY Event Layer—Help | ArcGIS for Desktop
the python syntax is
MakeXYEventLayer_management (table, in_x_field, in_y_field, out_layer, {spatial_reference}, {in_z_field})
And the Spatial_reference refers to the coordinates of you XY coordinates, not what you want them to be. You can also do this thru the toolbox. Make sure to choose the correct coordinate system for the input.
Also remember, that an Event table is not permanent, so you will want to save it as a shape of feature-class. If you want, you can use the projection tool from the Event table in geographic coordinates to a new projection,
Re the -99 values. I see a purpose for having records in a database with a set "no location" value (based on work I've done in the past). I suggest picking a coordinate that is within your extent, but a location that isn't needed (in the ocean, or lake....someplace obvious) then add a field with a flag each record as usable or not when doing calculations based on location. Reselect to eliminate these records from and of those type of calculations. Just a thought.
Many ways to do get to the same end game.