Generally in Germany, the word Laptop is also used. Another alternative is Notebook, usually used the same way that notebook would be used in English to mean the notebook type of laptop.
A quick look online has also found a few “joke” answers that have been used as well: Schlepptopp and Klapprechner. Schlepptopp combines the verb schleppen, which means “to drag or haul” (and is where the verb schlep comes from in English) and laptop. For Klapprechner, klappen means “to fold” and Rechner is the German word for a computer (literally “a calculator” in the sense of computing/solving a mathematical problem).