Re: I'm desperate....
I'm assuming both RAM sticks are the same here.
Grab Memtest86+ on a floppy, or get a spare CD, and then, pop out the working stick. Then, slap in the other stick. If it works, try testing it. If there's no errors, then try the other stick on the third slot, without the first one. If that works, put the first one in the first slot. If it doesn't work, there's conflicts with both sticks. You could always try the second slot.