Hello, I have a problem with an Acer Aspire 1604LC, build date July 2003. With battery on full power and power cord inserted, he just shuts down with no warning when working a few hours. The fan always turns at average speeds when this happens and it it not when I am doing things that can really overheat him (I do things that ask a lot of resources, but everything is ok then...). Any suggestions of what might be the cause? Thanks!