Basically, you need to back up all your documents, including music, photos, videos, and email. An external hard drive would come in handy for this. Actually you should be backing up these items anyway because you never know when your computer may fail.
Since you'll have to reinstall all your programs, you need access to them. Typically users have disks along with any license keys for this. If you downloaded applications, you need to be able to download them again and you'll need the license keys for them.
Then, you need the Windows 7 install disk and license key. Boot to the install disk to wipe your machine clean and install Windows 7.
Once Windows 7 is installed, do all the updates and install your malware protection applications. Then restore your files from the backup and install your applications.
Easy - right? It'll take several hours.
