So, I do love my 2007 Macbook but it's definitely getting on in age. Today, I got the always-wanted "Service Battery" message and figured I'd stop on by the Genius Bar to check. Sure enough, battery's dying. Now, the computer's almost 7 years old now but I'd like to keep it going as long as I can. I've upgraded this lovely unit from the 1GB RAM/120GB HD it came with to a 4GB RAM (3.5 recognized)/750GB HD and from Tiger through Leopard/Snow Leopard/Lion. I've got a few options but I'd love some second opinions on things. 1) Get a new battery. Granted, this is the easiest option and I'm checking the store I bought this battery from as it's under warranty. If not it's probably going to have to be another 130 dollar drop at the Apple Store sadly and I'd prefer to avoid that if possible. 2) Downgrade my HD from Lion to Snow Leopard (per the Genius Bar) to try to stop the fan from running super loud. They also suggested that I can attempt to clean out the computer but it's something I've never done. 3) If I can't get a new battery, I've been told it'll still run without one on AC power so that could keep it alive. (This will be battery #4 for the machine.) I've also been told I shouldn't run it on AC power all the time which was likely most of the problem. 4) Barring all of those, it may be time to upgrade. I've been trying to find a unit that I can still upgrade (probably just the RAM and HD like I've been able to with this unit) and won't run like a jet engine taking off. I'm fond of both Snow Leopard and Lion but it looks like most newer machines will only use Mountain Lion/Mavericks? I mainly use the machine for some light data entry tasks (so Safari, Word/Excel), some specialized programs (Aegisub, IRC) and I've also got a Bootcamp partition for Windows 7 for some of the programs I can't get to run in Crossover/Wine. Feel free to ask for other specifics on the machine itself, I'll be glad to mention anything that I can. Any other suggestions or help would be appreciated, thanks!