Firewalls prevent - but they don't repair. Only anti-virus and anti-spyware programs can reverse damage. So you should install a firewall on the computer that grants access to the computer, and then install an anti-virus and anti-spyware program on each of the remaining computers in the network. If you have files that shouldn't be shared (bank statements, credit card information, etc. To create your own .zip or .sit file, you can select a single file or a group of files from within Explorer, and right-click the selection. Again, depending on how you installed Winzip or StuffIt, you can click the "Add to Zip" or "Add to Sit" option and have these programs automatically archive the file(s) into one. The key is to understand what computer errors are, understand what they mean when they show up, and understand how to minimize their occurrence in the first place. Basically, computer errors are the result of a number of things that may or may not have anything to do with the way the computer is used. When executed, they would process each command without the user having to type each and every one of them. When Windows was developed, the need for typing commands was essentially eradicated thanks to the introduction of the point-and-click (mouse) interface. But this didn't stop the batch file fever that started under MS-DOS - and in some small circles, batch files are still as popular as they were in the beginning. The market for these devices extends from the highly technical and professional all the way to the pre-teen socialite. The product crosses all demographics and thanks to decreasing costs - it sees no economic boundaries as well. The Wikipedia encyclopedia claims that "Out of 1 billion camera phones to be shipped in 2008, Smartphones, the higher end of the market with full email support, will represent about 10% of the market or about 100 million units. Shareware is all over the Internet and it's really hard not to bump into it. The most popular places to find shareware is within thousands of download libraries, however the companies (and even independent programmers behind shareware) are increasingly offering shareware from their own websites. A simple Google or Yahoo search for a particular type of program will yield all sorts of results that point you toward items that you can try before you buy.