Computer hardware is really pretty reliable. Both hardware and software are vastly more complex than they were even a decade ago but software, more so than hardware, is the likely culprit in any kind of computing malfunction.
Clearly virus', trojans and worms are the main issues these days but the actual configuration of an operating system can have dramatic implications these days. OWT is happy to help you stay secure so feel free to ask us questions about your setup.
The problem that any network faces today with malicious attacks is probabaly way worse than you realize. Miscreants are constantly battering most any public network looking for issues and sometimes even an agressive probe can cause issues. It is more imporant than ever to have a well-configured firewall, up-to-date anti-virus and spyware software and a well patched and up-to-date operating system. Other software such as Adobe Reader or Flash Player must be updated frequently to stave off the latest exploits. Java is a real can of worms but if you need it - make sure it is up to date!