Inspiron 1200 Keyboard problem

Hi everyone,

Ive got a Dell Inspiron 1200 laptop which I recieved close to three years ago for use in a college classroom. About 6-7 months ago I started having this weird problem where, without any warning the keyboard would start inputing each key on the left two columns (the 1, 2, q, w, a, s, z and x keys) with their respective neighbor key. Example: Pressing the 'A' key results in 'as' or 'sa', the 'Z' key produces 'zx' or 'xz' and so on. This would last about a day or two and after that the problem would disappear for about a month and then it would happen again. While this wasn't a huge problem before its starting to happen more frequently now and for a longer period of time. Ive tried every solution I can find, the keyboard has never sustained any damage or had anything spilled/dropped on it.

Im assuming that the problem is that it has become defective, or is in the process of becoming defective. My questions are:

1. Has anyone encountered this problem before, and if so been able to fix it without physical repair or replacement?
2. If repair/replacement is inevitable, which would be the more economical solution? Im not sure what a ballpark range for the cost to repair the laptop would be but Ive seen superior models out in the $500-700 range, if were talking about a $200-300 repair job then it seems it would be more cost-effective to just replace it.

Thanks