Keyboards are constructed as a grid of rows and columns. Pressing a key connects a row to a column, which is how the key is identified. When a whole row or column stops working (3,e,d,c is a column), and only a single row or column, it is usually not the individual keys. It is more likely to be the internal wiring of the keyboard.
The row and column circuit traces often connect to ribbon cables that go to a separate little circuit board. Those ribbon cables can develop a bad connection, the circuit trace for the column or row can get damaged or have a bad solder joint, or there can be a failure on that little circuit board. If you have some technical skills, you might be able to identify the problem and repair it. There are a number of online tutorials, such as this one.
If the problem involves multiple keys that are not entire rows or columns (e.g., a whole column plus some other keys), the problem is often that something spilled on the keyboard. There are many sources on how to try to repair that.
This also just started happening with my Dell Inspiron 1720. But it seems intermittent... sometimes they work sometimes they don't. Weird. – Charlino – 2010-03-26T01:57:04.553
please provide some more info: make and model of your laptop? operating system? and are you sure it's not just a case of Fn Lock or Num Lock? – None – 2009-12-08T04:14:01.273