There can be several reasons for a bluescreen, especially if it happens with all your games, not only RO.
Your RAM is pretty low for recent games and applications, but if you're running on Windows XP or lower, this should be no problem.
If bluescreens only appear when you play, there is a high chance that there is something wrong with your RAM (physically, I mean, at least one of the modules may contain errors/is damaged), with your video card or your video card driver. I suggest you to go through your device manager, and update all of your drivers, especially SOUND and VIDEO CARD drivers.
To open up the device manager, do this:
Try clicking start->run
Type the following command in and click OK:
devmgmt.msc
Another possible reason might be your HDD. Either it's too small (too much free space is used, so there is no more space for the virtual memory), or it's damaged and the system tries to write on one of the damaged sectors. Click on start -> run, type in "cmd" (without the ""), click OK, and type in "chkdsk", it will do a quick check of your current HDD partition, and will say at the end if there are any bytes in damaged areas.
Also useful to find out the reason for the bluescreen is one line in the bluescree where a driver file is mentioned. Example:
In this case, it's called "aries.sys". If it happens again, try to catch that name before the computer reboots, then google it to see if it's part of your video card driver or any other driver.
