1. Are you comfortable with removing/installing memory modules yourself?
2. If yes, do you have more than one memory module? Try to remove one memory module to see if it works.
The key is isolating the problem. Giving you an example -> I spent more than half a day installing windows 7 on a PC which shouldn't take more than 30 mins normally. The problem was it would install 90% of the way and come up with a bluescreen. After a million attempts I tried connecting my monitor via a VGA cable instead of a DVI and guess what installed fine. Connecting back to a DVI AFTER the install was fine but just not during it. And this was only on this particular PC.
The point of the above is there are times when things do not make sense. The only way to solve an issue in such a case is by trying to isolate the problem. Sometimes it might be completely unrelated (eg I'd have never guessed that a display cable could waste half of my day!)
Regarding losing your data, it should be fairly simple. If you do not have a spare laptop, get a USB HDD case for laptops < $10 on ebay. Make sure to get the appropriate version of the USB HDD case (eg SATA?). Remove your hardrive from the laptop, plug it in the case and connect it to another machine via USB and copy of all your data.