I needed to remove the hard drive from my aunt's 5100 laptop, and back it's data up. Now, I've put the drive back inside, and i'm going to re-install windows. However, when I turn it on, it says that there is an incorrect power adapter, and that the laptop will be running on it's battery.

I didn't test the adapter before I worked on the lappy, and I suspected that my aunt sent me the adapter for her older inspiron. So, I bought a targus 90w universal adapter, which specifically mentioned on the back it worked in the 5100.

I've removed and re-installed the hard drive & memory. When I try booting with just the ac adapter, the lights on the front blink, and then it goes dead.

Any help would be great...

Any update on this problem? I am having a similar issue... Was using a proper 90W power adapter for my Dell Inspiron 5100 until the connector tip was damaged. I replaced it with the wrong power adapter (60 or 65W) and it worked for a few days until at point it just stopped charging, and now it won't power on at all. I just get three quick amber blinks followed one green blink