1. Restore the RAM to its original condition. See if everything is OK.
2. Then carefully add the new stick and check again.
3. Final test with the program on www.memtest86.com (let's you make a bootable diskette that runs through the memory for a few thorough tests).
This is assuming you added a stick. You're not clear on that.
Are you sure you've got the right kind of RAM (same as the old one) and the configuration is supported by the motherboard?
Hope this helps.
Kees
First and foremost: I realize now what I did was incorrect, and I'm afraid that my actions may have ruined my computer! I was trying to install new RAM in my computer and stupidly was working on carpet. I opened the case twice: the first time I monkeyed around, my computer worked when it was started up. After the second time going through the computer, it started up by then restarted after getting to my desktop. Then it started to beep two different tones like a European ambulance. What should I do now...?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic