RAM makes a whale of a difference in the way a machine performs, doesn't it?
I wish I could look at the motherboard....
There's a lot to be said for hands on troubleshooting. I'm debating flashing the CMOS...I don't know that it will help, but then again, it's surprised me more than once...and with the current state of things, it sure ain't gonna hurt.
To do this, you need to remove the CMOS battery. It's about the size of a quarter and is usually located in the lower right quarter of the Motherboard. Near the battery (either below or to the right on most) you should see 3 small pins with a jumper block on them. It should look like this, where the underscore represents the jumper
. . . Move the jumper to the other pins
. . . for about 30 seconds and then move it back to it's original position. Put the battery back in, making sure to put it in
+ side up. Try to boot your machine.
Note that this will clear the date, time, and restore all default settings to the BIOS. You will have to reset any settings you have changed such as Boot Priority. If you are not using a static strap, keep one hand or your arm touching the metal part of the case to prevent static discharge damage to the Motherboard and it's components.
Let me know how it goes...