I'd forget tests. But to offer this advice I have to know if you know how to clean the vents and replace heat sink compound.
Also, something is odd about the reinstall Windows. It sounds as if you installed a retail copy. That is trouble for most as I rarely find it installed proper today. Overheating can be the result.
I have a four year old Toshiba Satellite A300 series laptop running Vista. Within the last 6 months, it has seriously slowed down. Starting programs and shutting down the laptop takes forever. My internet browsers constantly freeze up (even when simply reading a news article), causing me to either shut down or close the browser via task manager. Booting up takes more than five minutes at times from complete shut down to the point is finished loading and can be used.
Since about the second year of having it, the CD/DVD fails to be recognized after the computer being on for a while.
To use it, you have to restart the laptop a few times.
The fan runs constantly. Within the last month, the laptop has started overheating and shutting down. After a few days, it then started shutting down after less than three minutes of being on even when the laptop was not overheating. Oddly enough, I could keep the laptop on in Safe Mode (unless I was using the internet heavily, then it would shut down) for good half an hour or more. I would say about 1/3 of the time after restarting the laptop after rebooting it does make a loud beeping sound.
I also keep getting this error message saying the USB device cannot be recognized. Interestingly enough, there is NO USB device plugged in... My fan is also making a very irritating "whir" sound after being on for a while.
I love my laptop, but it seems like in the past few months, everything is starting to have operating issues. We have a large I.T. staff at my work. I consulted the IT Director and he indicated he felt the motherboard is failing. I also asked one of the help desk guys and he said the same thing. So just to be safe, I took it to the local computer repair shop (which has high reviews) and they took the laptop apart, found some dust in the fan, but otherwise found nothing. They determined the motherboard is failing. I asked if there was any chance it could be the hard drive and was told no.
By chance of luck, I remembered I purchased the extended warranty from Circuit City. After calling, I found they were still honoring them. I told the customers service guy what was wrong and he stated the motherboard was covered under the warranty. I packed it up and shipped it to them. It came back and all they did was replace the hard drive. They said they "tested" my CD/DVD drive, USB ports, motherboard, and fan and found they were all operating fine. They did not even reinstall Windows!
After taking hours to reinstall Windows, I found nothing has changed with my CD/DVD drive or fan. To add to the injury, now the web cam keeps saying it failed, It has not cut off, but the it did beep once when restarting after installing the 120 Windows updates... I'm furious that I'm still having the same issues, minus the cutting off.
With this being said, I'm hoping for advice on what I should do next, what tests I could run, or if anyone else has had any experiences with City Assure. The warranty is going to run out at the end of April. I believe they "smoothed" it over by temporarily fixing the problem with a cheaper fix. I'm afraid after April the motherboard will give out and I will be screwed out of the $350 I paid for the extended warranty.