Question in hardrive and software?

there r 4 questions: 1. how do u clean the inside of your hardrive and the fans when they get dirty? i heard that there is this kind of thing that sprays air out and blows the dust away. 2. how do u open up your hardrive so u can clean the dust inside it? 3. i'm using norton antivirus 2005 and i heard that when u r scaning your computer, u have to do it in save mode, so do i HAVE to do it in save mode and what will happen if i DON'T do it in there? 4. i'm using spy sweeper and spy subtract, and on some days it says that it's updated and my computer is protected from ... traces so do i just leave the software as it is or do i have to do something else. I NEED SERIOUS ANSWERS AND I'LL ALWAYS CHOOSE A BEST ANSWER.

Question in hardrive and software?antivirus protection

I haven't heard of people cleaning the inside of their hardrive. Basically the hardrive is a very delicate hardware. If there is dust INSIDE the hardrive, it would be problematic. I don't think dust will go inside the hardrive though. As for the fans and other hardware, just go to your local hardware/ computer store to find a can of compressed air.

I don't think there is any difference in scanning your computer in Safe Mode or normal mode. However, this is what I find in some sites: "It is good practice to run security software scans in Safe Mode to ensure maximum results. If you don't scan in Safe Mode, the security software may not be able to detect or remove all of the security threats it finds." My personal opinion is that it doesn't really matter that much.