The easiest method is to use Windows Update.
- Go to the Windows 7 Service Pack 1 download webpage on the Microsoft website, and then click Continue.
- Choose either the 32-bit (x86) or the 64-bit (x64) version of SP1 depending on whether you're running the 32-bit or the 64-bit version of Windows 7, and then click Download.
- To find out which version you're running, click the Start button , right-click Computer, and then clickProperties. Under System, next to System type, you can view the operating system.
- To install SP1 immediately, click Open or Run, and then follow the instructions on your screen. To install SP1 later, click Save and download the installation file to your computer. When you're ready to install SP1, double-click the file.
- On the Install Windows 7 Service Pack 1 page, click Next.
- Follow the instructions on your screen. Your computer might restart during the installation.
- After installation is complete, log on to your computer at the Windows logon prompt. You might see a notification indicating whether the update was successful.
- If you disabled your antivirus software, enable it again.
I would highly recommend not using Internet Explorer for the following reason. IE is the one of the most used browsers and as such the vast majority of malware/viruses target IE as they way into your system. For this reason I would suggest using a different browser that isn't susceptible to these attacks. You don't want to be the low hanging fruit. Firefox, Opera and/or Google Chrome work just and well and in some cases better and faster.
Electricity takes ALL paths back to the source, not just the least resistive. -Guido