>>Also verify that the laptop isn't getting abnormally hot. If a fan is dead or blocked you could have an overheating problem.
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>Thank you both Al & William. He went into some repair shop yesterday and they detected a bad hard drive and said they are going to replace it for $400 (250 for 80GB drive and $150 for work). Sounds like too expansive to us, so we may want to try your advices first.

A good 2.5" laptop hard drive with a 5 year warranty (e.g. Seagate Momentus 100GB) is under $100 e.g. http://www.ncix.com/products/index.php?minorcatid=1044

As for installation - the preferred method is not simply to put in the new drive and reinstall everything. If the hard drive has not yet failed, they can probably run SpinRite (or equivalent program) on it to make it clonable, then clone your old HD to the new one.

Each of those steps takes a couple of hours, but the way it works is:

- boot SpinRite from floppy or CD, start it running
- walk away and do something else while SpinRite works (could be several hours)
- examine SpinRite results when it's done
- time involved for the tech to use SpinRite: probably less than 15 minutes

Assuming SpinRite has made the drive fully clonable, then:
- connect old and new hard drives to a suitable computer
- start up cloning program
- walk away and do something else while the cloning program runs (could be several hours)
- examine cloning results when it's done
- time involved for the tech to clone the drives: probably less than half an hour

Any competent shop will have other things they can do while they're waiting for SpinRite and the cloning operation to complete. Don't let them charge you for the full time.

After the above operations, not only will you have a new hard drive installed, but all your programs and data should be available just as they were with your old hard drive, so you won't have to reinstall anything. It should be exactly the way it was.

The only potential risk is if the drive is sufficiently bad that SpinRite can't recover it. However, this isn't much of a risk, the tech has only spent 15 minutes of his time to determine this. If SpinRite can't fully recover your old drive, then:

1. You'll need to back up your data to an external HD, DVDs etc.
2. Let the shop just take out the old drive and put in the new one (this should only take a few minutes)
3. Reinstall your programs, and restore your data from your backups

As others pointed out, if the tech is opening the computer to change a hard drive, get them to clean any fans/filters etc. to make sure air flow is normal and all components will run cool.