Having problem starting my 2007 Rav4 every second day.

You have a power drain in the system, Either take it to the dealer or trusted mechanic, have them put a breakout box on your system to find the drain, or you can put a DVM on your battery and start pulling your fuses one by one until you find the fuse that's causing the drain, then you can trace that circuit to find out why you have the problem.
Also, before doing all that, you can sit in your car at nighttime doors closed and see if an accessory is staying on, I myself recently did this because of battery drain and found my glove box light was staying on, even though the door was closed, the hot Florida sun warped the door just enough so that it wouldn't push the switch all the way to shut it off.

Careful - had same problem with 2003 rav4 turned out it was nearly running with no oil even though the oil level warning light didn't light up - check your oil level before you drive the car again

Check all the interior lights in the truck, look at the visors which are the single biggest cayuse of the battery drain, look at night. Also Have the batteries tested, a shorted cell will draw them down as well. Never overlook the obvious.

Most of the time a car's computer is on at all times. Try disconnecting the positive cable to your battery with the key out of the ignition.Depress the brake pedal a couple of times;this should drain the power in the computer.Reconnect the positive cable and the car's computer should be rebooted.Good luck!

I would say that both issues are related. Which isn't good news, but at least when you find your pwer drain, it will make perfect sense. If have tried many time to piece meal troubleshooting a problem like this and just wasted time, by not doing it right.

You will need an accurant clamp on amp meter, to do it though. You clamp it around the main battery cable (red side) - pull all the fuses out f your fuse box and then one at a time put them in an write down what the reading is. Once you find the drain (high amperage pull although it is off) then you can look at the fuse panel diagram and figure out what it controls.

Make sure you know the fuse panel layout and sizes before you start.

Batteries sometimes die completely for no apparent reason even though they were working fine only minutes beforehand. Try a new battery and also get the charging rate checked by a knowledgeable person.

This diagram should help you find the oil drain plug for an 07 Rav4, and also how to change the oil and filter: http://members.cox.net/rav4/01900210.pdf

Check the radio fuse. As unusual as it seems, GM has started having the radio (even though not turned on) generate the chimes and turn signal sounds. If the radio fails, all the chimes fail too.

This applies to other vehicles besides the HHR. My 2003 Silverado had the door chimes fade down so I could barely hear them. The fix was to replace the radio (under warranty, fortunately...).

It's possible that the battery is shot even though it's a newer car. I have a 2006 Ford Taurus I had to replace the battery in 2007. You just never know with batteries. Do you have 5W30 oil in the car?