Let me know how it works out. Most of the time when I hear fans sound like that at work, it's because the processor is getting too hot. Occasionally it is the fans themselves. For a while Dell had a defect with their business model machines, that caused them to overheat and sound like Jet airplanes taking off. Sometimes replacing the fan would help, but often we'd have to RMA the motherboard. If you're seeing your total CPU usage jump to 100% when you aren't running any intensive games or other production / rendering type software, it could possibly be because of corrupt files in Windows. Most of the time, it is a cooling issue or problem with the motherboard, but Vista is a royal piece of garbage, so it's hard to say. If you know somebody that has PC knowledge and can install Win7 for you, that's really the way to go, but I would do the following just to rule it out: 1. Hard drive error check (In 'My Computer' right click drive C: and go to tools) 2. System files integrity check (open a command prompt and type SFC /scannow) 3. Disk Defrag - I don't remember if Vista does it automatically like 7 does. 4. Run ccleaner and clean temp files and also do a registry check.