Please can anybody help me out cause i'm losing my clients?

My workstations have problem of Hardware malfunction.

The message that I'm getting immediate when the systems are powered on is "Alert! Uncorrectable memory error previously detected in 3FC78000h for one system and 075A7000h for another system. Strike F1 key to continue, F2 to run the setup utility.

After striking F1, the system will boot to the OS then after 3-5mins it will display blue background with text "*** Hardware Malfunction call your hardware vendor for support.

*** The system has halted ***  

Troubleshooting steps that i have taken were I reseat the RAM cards, then removed and replaced back the mother board battery. 

The workstations operating system is Window XP.