Although the drive may very well need to be cleaned, there hasn't been nearly enough troubleshooting to establish whether a dirty drive is his problem. Indeed, it might be argued that it has not been firmly established that there is a problem. Given that uncertainty, perhaps running some diagnostic experiments first, to narrow down the possibilities, is an advisable course. Generally speaking, it is not hard to put together a suite of tests that are "high yield" in the sense that they take little time, but can save huge amounts of time.