If your referring to the machine in your siggy. I'd advise to leave well alone, mate. Unless an update is going to add something specific that you want/require, its not worth the hassle at the best of times tbh.
With your machine being an eMachines (God I hate Dixons
) chances are your motherboard will be either some unbranded name or reworked by eMachines. If your hearts set on it, first call is the eMachines and/or PCservicecall website. Failing that get some software and find out what make/model your Motherboard is and continue at your own risk.