Re: I sniffed a burning smell coming from my computer...
I have had so many "burning smell" experiences with my computer its not even funny, there's about 4 things that usually can smell, PSU, motherboard, your CPU paste if your HSF comes loose, or like you said dust getting hot, both times my PSU and MOBO smelled it was already after they died, so I would just double check if the HSF was secure and if it doesn't smell no more I wouldn't worry about it xD.
I've only had my computer since January and I've already had every one of those things happen to me except the dust cause the computer hasn't worked long enough to get dusty lol xD
OS: Windows Vista Ultimate 64-bit
MOBO: ASUS M3N72-D (AM2+ Socket) CPU: AMD Phenom II 965 x4 Memory: 2GBx2 800 DDR2 Ram
HDD: 320GB (298GB) WDC WD3200AAKS SATA HDD2: 1TB WDC WD1001FALS SATA
Video: 8600GT OC Sound: SoundBlaster X-Fi Xtreme Audio PSU: Thermaltake Toughpower 750W