Some advices for Windows User.
Do not switch to Linux. Windows gives you support from great community of its users. Linux support, obviously great, is limited to small (very small, I might say) group of friends and - mainly - Internet. While without Internet connection, or troubles in name the problem, you could find no solution. If you want to test Linux, you are wonder it is for you or not, you can easily use "Live CD". It is C or DVD disk with full Linux installation. Because of the medium (CD-ROM drive) it is slow and it doesn't allow to make changes in system preferences (CD is not rewritable), but gives you opportunity to see and use Linux and many of its applications without any changes in your Windows installation.
OK, we have old, good Windows. With its easy of use and great community now we have to defend from trojans and viruses.
The first and most important thing is to not install any application you can get. It requires some effort, but you will get back double. It saves you from viruses attached to applications. Please remember to not afraid of copying or moving programs on disks. Virus is danger only if run. It means it cannot do anything until you start (click/double click) it. Simply delete any application from insecure/unsafe/dubious source. If you meet all of this rules, you do not need antivirus software (simplifying. problem)
Old days the only way of infecting was to get floppy disk and run a program from it. Now while you surfing on the Web the Web browser execute many small programs and use many complicated resources. It is possible to get into troubles viewing a static image - because browsers are very complicated programs and on a way from network card to screen they have to make many instructions witch can affect your computers security. That's why you shouldn't allow to run unsecured programs (browsers) on you computer. The leading one is MS Internet Explorer. It is very nice and clever tool, but in this case of choosing between usability and security we cannot choose comfort and then try to make it secure. When you open Internet Explorer there are only minor actions you can take to avoid infection. So - please use another web browser. For example Firefox or Opera. But even if you use them, please ensure you do not install ActiveX support. It opens a way to your computer for trojans. At the end you can avoid untrusted web sites and refuse unexpected downloading files from Internet. In most cases it is a dialer or trojan, which is hide in porn movie or very attractive screen saver.
It is not possible to keep Windows safe all the time, but you can try. The simplest and not confusing way is to:
1. not to use MS Internet Explorer
2. not to experiment with strange websites
3. do not download anything unexpected (dialog box with buttons "Save" and "Open")
Here are some more tricks you can use to make you computer more save. It requires more effort, but makes the period when your Windows is usable longer.
Administrative account. You log on administrator account by default. It is necessary to make another account without administrative privileges and to start log on it. You might need the admin account only if you want to install new software, but there is a trick - press Shift and then right mouse button simultaneously. From menu choose "Run As" and then in small dialog box enter account name (Administrator) and its password. Unfortunately you loose your all settings if you don't make the change just after installation. You can copy all settings, but it is not very easy operation.
Thats all by now. To be continued :-)