Basic Windows XP currently has very poor security support. Fortunately there are reasonable (and fairly cheap) third-party products to take up the slack. The Privacy Software Review site has detailed reviews on numerous products however the most useful I've found are:

• DriveCrypt is a great package for creating encrypted virtual disks using AES, Blowfish, and a variety of other encryption algorithsm. Ability to make portable encrypted virtual disks that can be mounted on any machine.

• SpyBot Search & Destroy detects and removes spyware which is critical if you use Windows since new ones seem to appear daily.

• LavaSoft Ad-Aware rocks at finding and detecting spyware. Definately useful in conjunction with SpyBot. They also sell Pro/Plus versions which provide always running early detection to avoid getting the spyware installed in the first place.

• JavaCool's Spyware Blaster also helps avoid spyware being installed via IE including tracking cookies, ActiveX scripts, etc. Not convinced yet that this is better than Ad-aware Pro, though it is free.

• Windows Washer removes browser tracking history, recently opened files, secure erase of files, application plug-ins, etc.

• ZoneLabs provides ZoneAlarm, a great personal firewall for Windows, free for non-commercial use.