Thank you very much Maverick!
This is something like what I was seeing today. However... isn't there a solution with a longer-lasting battery? For this HP they declare 2 hours. A co-worker of mine also has an HP similar to this (with a Pentium T4200 CPU) and her laptop battery also lasts about 2 hours.
To have a long lasting battery am I forced to go to a model with a much less powerful CPU (like the Core 2 Duo SU series) or is there something in the middle?