Make Regular Backups!
If disaster strikes, you'll need to be able to recover your programs and your data. In both cases, you won't be able to fix things unless you're pre-prepared.
For the programs you rely on, make sure you know where the CDs are before you need them urgently! You may also need "software keys" if you need to reinstall.
Backing up data is more difficult to get right than you might expect. If you're not systematic about it, you can end up with several versions of any file, and find that no single one of them has all the latest updates. You should test your backup procedure regularly to check you can recover useable files, and that you know exactly what versions you're able to get back. Every situation is different, so ask for advice before it's suddenly a critical issue.
You may also like to consider automatic data protection software, such as GoBack. This runs in the background on your computer and tracks changes that you (or a virus) makes. Provided your disk is not destroyed in a disaster, you will be able to "turn the clock back" very easily to a time before the incident. Contact the present author for more information about pros and cons of GoBack, and how to configure it.