I've an HP dv6-2190us laptop, usually I use it with power adapter connected while battery is removed. I bought it 14 months ago and I'm sure that the battery hadn't reached its charge cycle, but it cannot keep the laptop turned on for more than 30 minutes, in the first weeks I could work about 90 minutes with battery. Is there anyway to revive the battery life? (I haven't any external device connected or many applications open)
There are a lot of ideas out there about how to handle a battery memory. Here's one simple method some claims to be effective - though that seems like that wouldn't really work to me. Interestingly, this rant seems to directly contradict the first reference.
Ultimately, your options and required approach are completely dependent on the type of battery in your machine. Given the age of the machine, I'd assume your battery to actually be a Lithium Polymer (I think Lithium Ion means the same thing). According to random people over here, you can't remove a memory from a Li based battery. But of course, it seems no one can really agree about that.
The method mentioned by music2myear may be helpful, but I don't know if that's a method meant for Lithium Polymer batteries - though he does mention "LiIon particles" - so it probably does apply.
My recommendation is you try a few of the above suggestions (and music2myear's). Report back here what level of success you have to help others. If none of that really helps you, then you may consider just buying a new battery. Indeed doing so would likely improve your battery life quite a lot ;) -- though if you were to find that didn't, then I'd assume you're just doing very power-hungry things now and weren't previously.
You can try tightly wrapping the battery (after it has cooled from use) in plastic wrap and then placing it inside 2 layers of quality zip-loc bags and freezing it for a couple days. This tends to resucitate a few of the LiIon particles and is generally recommended for phone batteries.
UPDATE: Removed unhealthy advice for LiOn batteries. See comment from person who is not Kyle below.
Other than that, there are expected lifespans for batteries. And new batteries are not incredibly expensive either. The lifespan of a battery, due to it being a chemical reaction, varies greatly depending on usage and environment. 14 months, under certain conditions, is not an excessively early point at which the battery will fail. After all, for batteries especially, there is no guarantee the battery may not be much older than the computer it is installed in.