Computers typically run just fine when you first get them but then slowly degrade. Even after loading Windows 7 as a clean install I was still experiencing a slower laptop than I remembered when I purchased it 2 years ago. Windows startup/login time was just too slow.
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Using Speedfan (download here) I noticed the laptop was running a little hot, about 140°F and the cooling fan was operating all of the time. Speedfan also measures the actual CPU speed and my dual core cpu’s were running at only 900Mhz. The Intel T2080 Dual-Core CPU installed in the laptop is rated at 1.73 Mhz, so I was losing almost 50% of the rated speed. This additional CPU information is on the new ‘exotics’ tab of Speedfan (see graphic). I replaced the cooling fan with a brand new one I got off eBay for $20 and the laptop is running at full speed now!! (Speedfan CPU numbers are not dynamic like the temperature and other numbers, the speed reported is at the time Speedfan was started. To get a good sample exit and restart Speedfan several times).
JPWhite's Tech Blog 