Laplink has released PCdefense, a security tool to protect PC users from spyware. The firm said the software is designed to prevent spyware from being installed, rather than focusing on detecting and cleaning spyware already on systems.

PCdefense monitors the Windows registry for any changes and alerts users about attempted software installs. It also blocks keystroke logging and warns the user if a program is trying to capture their input.

Spyware and virus cleanup tools are also included, but the goal of PCdefense is to stop malware from ever getting onto the system, Laplink said.

"Our rivals do a clean-up after infection, similar to the approach of antivirus tools," said Laplink chief executive Thomas Koll. "The problem with this is that you can also lose the use of your PC through some threats such as rootkits." Because of this, PCdefense includes a disaster recovery tool that backs up applications, settings and data. This feature is operating-system-independent, allowing users to restore their work environment onto a new PC running a different version of Windows.

A SpyAlarm registry tool enables the user to allow or block any application, maintaining both a whitelist and blacklist of allowed and blocked software. Both SpyAlarm and an Anti-Keylogging tool keep a history log of alerts and users' decisions.

Repair and administration tools allow the user to see what runs at startup, and to view and edit browser cookies, and see any settings in the Hosts file on their PC. Such settings can be used to redirect web requests to spoof sites.

PCdefense is aimed mostly at individuals and small businesses, but will also appeal to organisations with mobile staff outside the corporate firewall. " Banks are also asking for solutions they can give to online customers to combat identity theft," Koll said.

PCdefense will be available first in the US for $49, but a UK version will ship within 90 days and is expected to cost £35.