Works in: 7 If you like charts, numbers, and data sets, Windows 7 has just the tool for you. Performance Monitor tracks your PC's hardware and applications in real time, generating all kinds of data that you can review and compare. It's aimed more at system administrators than at everyday users, but if you're trying to confirm a sneaking suspicion that, say, iTunes is single-handedly tanking your system's performance, it can help.

To access Performance Monitor, press the Windows key, type perfmon, and press Enter. You can start assessing your system by expanding the Monitoring Tools folder and clicking Performance Monitor. From there you'll probably need to delve into the built-in help files, as the tool isn't exactly user-friendly. For more, check out the .

Still looking for a good reason to ? One word: security. The new OS is inherently better at fighting infections, blocking hackers, and thwarting phishing attempts. And with the extra tools described here, you can lock it down like a digital Fort Knox.