The security of your corporate data and the integrity of your company network are put at risk whenever you travel with a business laptop. That's because the laptop is no longer protected by the physical security that your office provides, or the security systems designed to protect the software running on it. And any malware that gets on to your laptop has the potential to infect other devices on your network next time your laptop connects to it.

But mobile security need not be expensive: here are ten ways you can minimize these risks to your laptop at little or even no cost:

1. Encrypt the hard drive

If your laptop is lost or stolen, anyone who gets their hands on it could steal your data, read confidential emails, communicate with your contacts, and possibly even connect to your corporate network and cause even more havoc.

The best way to prevent this is to encrypt the laptop's hard disk so that a password has to be entered before the computer will boot. This will also make your data inaccessible even if the hard drive is removed and connected to another computer.

For laptops running Windows Vista Ultimate or Enterprise you can use Microsoft's BitLocker utility, included with the operating system, to encrypt the system drive. For other Windows, Linux and OS X systems the open source TrueCrypt application will do the same job for free.

2. Use a VPN

Connecting to the Internet from a business center, Internet cafe or airport hotspot presents a serious security risk as these are environments where it is relatively easy to intercept your data. A VPN encrypts all data before it leaves your laptop, and keeps it encrypted until it reaches a trusted environment such as your home or office network. If your company doesn't provide a VPN, try the free OpenVPN. Simpler to use solutions include paid-for services like HotSpotVPN which uses OpenVPN, or remote access services like GoToMyPC or LogMeIn, both of which use data encryption to connect your laptop back to a trusted office or home network.

3. Update and patch your software

Most operating systems allow you to download and patch your system automatically, so it's wise to ensure that this option is enabled to prevent it being vulnerable to known exploits. (Most systems recently infected with the Konficker worm had had Windows update disabled.) You can check for updates to common Windows applications using Secunia's online software inspector.

4. Run a firewall and anti-virus software

There is some debate about how necessary anti-virus software is on Macintosh and Linux laptops, but it is wise to err on the side of caution. At the very least you should ensure a firewall is running. ClamWin is a free anti-virus applications for Windows, available from http://www.clamwin.com.

Alternatively, use a portable security device such as the Yoggi Pico USB security appliance which includes firewall, anti-spam and anti-virus scanners and intrusion detection on a device the size of a USB memory stick.

5. Bolt down your browser

If you use a Windows laptop, switching from Internet Explorer to Firefox means you are less of a target to hackers. You can enhance you security further by installing several add-ons, such as NoScript which can protect you against cross site scripting and clickjacking attacks. We've recently provided more coverage about security add-ons for Firefox, too.