Lenovo 3000 C200 turns on but fails to start

Question

Greetings all!
I have a problem with my Lenovo 3000 C200 and I'm hoping someone can help. Please be patient with me as I'm not as good with computers as I am with larger equipment. The problem goes like this:
I bought the laptop used about a year ago, running Windows Vista Business. It has worked without any problems until a recent work related trip to California 3 weeks ago where a balloon popped up telling me Windows Live OneCare was expiring and I needed to uninstall it and replace it with a different antivirus software. I didn't think much about it at the time and was going to install the newest version of Norton when I got home and back to work but before I could, I started getting the following error messages popping up on the screen during startup and intermittently while the computer was running
SYNTPENH.EXE (code 0cx0000142)
RTHDVCPL.EXE
MSASCUI.EXE
PHOTOSCREENSAVER.SCR
SHELLEXECUTEEXFAILED (code 3221225794)
one of the guys I work with suggested I uninstall Windows Live OneCare and restart the computer but when I tried I noticed the "change/remove programs" prompt was missing. Also, I was unable to open Word documents, Excel files, download programs from the internet, etc.
another coworker suggested it might be a virus or Trojan and attempted to connect his laptop to mine via a Belkin Easy Transfer Cable, thinking he would scan my hard drive remotely with the antivirus software on his computer and remove anything harmful. As soon as the cable was connected, it flashed an application error message on the screen of my Lenovo (I didn't see exactly what it said) and about 30 seconds later my screen went black.
Now, when I press the power button, the fan comes on, it starts to make noise, the CD drive will start to spool up (if there's a disc in it) but stops before actually doing anything. Doesn't seem to matter if it's plugged in or running on battery, none of the F keys seem to do anything during this time and the screen never comes on. I've tried running the boot disc that came with it but no luck there either.
I don't use this computer for much other than checking email when away from home, charging my phone and ipod and watching movies or doing paperwork on the plane. Unfortunately, I'm away from home a lot so it's pretty inconvenient to be without it!
If anyone has a suggestion I'd really appreciate the help! If you've already covered this someplace else, please forgive the repost. And sorry for the book, just not sure what info might be helpful.
thanks in advance!
Roger

Answer 1

Ok, here's the results:
Tried plugged in but with battery out - no change
Unplugged, removed battery, held power button for 30 seconds, reinstalled battery, replugged - no change
Removed memory modules and reinstalled in original positions - no change
Removed modules and tried one at  a time in different positions - this did change things! One module had no change in either location, the other allowed the computer to start and run (back to the point of the original problems with the error messages and unable to open word docs, etc) in both locations. Installing the second (bad?) module in addition to the "good" module caused the computer to not start again, removed it and computer restarts fine.
So I'm guessing I need to replace the one apparently defective memory module and see if that takes care of the rest of the problems? Or is there something else I need to do to address the error messages and functionality issues?
And by the way, thanks for all the help!