It's always difficult ordering replacement electrical items on-line, I'm never really 100% sure if I'm ordering the right one. However, when the charger for my son's laptop packed up, I needed to replace it pretty sharpish. After all, he needed it for exam study (at least that's what he told me".
Having read the other reviews, and looked at alternatives, I plumped for the Compaq Presario CQ61/CQ71 Laptop Adapter Charger. It turns out that it was a good choice: cheap, and a perfect replacement for the broken one. It doesn't even seem to run as hot as the original either, so no overheating problems, and it doesn't keep dropping out.