Acer Aspire 5014 WLMi cannot start due to RAM mishap

Hey there. Really sorry to make my first post on the forum a plea for help, but I'm a bit desperate.

Long story short, I tried to install new PC5400 RAM in my 5014 WLMi instead of PC2700. When I turned it on after putting the new RAM in, it didn't start up (power and hard drive light turned on, that was it). I then realised I'd done something very stupid, and put the old RAM chips back in. Turned it on again, and I didn't get much of a reaction - the power button lit up, but screen showed no signs of life.

If it's of any significance, holding the power button for five seconds shuts down the computer with the old RAM in it, but if it's got the wrong RAM, it doesn't respond to anything but me unplugging it and taking out the battery.

I suppose my question is, how bricked is my laptop, and what can I do?

Thanks in advance for any help.