First you have to take a real look at the power supply besides replacing the board. A prebuild like that sees a 305w supply for the P4 board currently in. Another problem is ordering the wrong type of memory for any board you order from newegg. Even the two Socket 423 boards run DDR2 not DDR memory.
The idea of bringing to a shop would be to find out if the slot is actually bad and having them find a suitable replacement board. Otherwise you are practically looking at a new build by the time you end up with the new board(manufacturers recommend 350w minimum for atx boards), memory, a larger supply, etc. while EBay or some leftover replacement boards may still be found.
The first thing you may want to try there is a free System Info for Windows tool that will list everything about the hardwares and even softwares installed as well. It comes in two forms as a stand alone you simply double click once downloaded to a folder or the newer release that creates a folder in the Start>Programs menu. SIW Download - Softpedia
The general information page is seen at SIW | System Information for Windows by Gabriel Topala
It's a small and very reliable tool unlike programs like PC Wizard which sometimes give off false cpu temps due to being software geared over a simple basic information gatherer.
Once you know the exact make and model the board is you can run a search to see if another one can be found. For seeing a large update that would mean investing in all new hardwares as well as case and supply which you weren't planning on at this time. Ebay, Amazon, or another similar site may likely see the equivalent board that will drop right in while choosing a newer board?