Hello. I have an Acer Aspire 5100 laptop with Windows XP Media Center Edition. This past weekend, I tried to upgrade to 4GB of RAM. After replacing the old RAM sticks with the new, I am getting nothing but a black screen after turning on my laptop. The mouse and keyboard I usually keep plugged in the USB ports do not work. There is no sound, nor does any monitor that I've tried hooking up to my Acer display anything as well. I've tried every key combination I could come in mind with, but nothing works. I can't access the BIOS, nor anything else. The HDD indicator light flashes green for only a few seconds after powering up the laptop. I'm not for certain if the laptop keyboard is functioning either. I'm unable to turn the NUM LOCK on or off. The CD/DVD drive runs normally, I assume. I'm able to pop in a disc and can hear it running normally. I've also tried placing the old RAM I had previously used back in the laptop, but there is still no change. I've run out of options and am curious if anyone here would be able to assist me. Your help is much appreciated. Thank you.