avast, zone alarm and tea timer damn near use 256mb by themselves. download freemem, so that you can tell that most of your ram is being used up
I've been saying this for awhile, but people ignored me
Most experts recommend at least 512MB of RAM for XP; some people upgrade to 1GB, 1.5GB, or even 2GB of RAM to put issues of insufficient memory and sluggish file swapping to rest. If you use the PC mainly for office applications, the Web, and e-mail, then consider upgrading to 512MB of RAM. If you run a lot of applications at the same time, frequently use large databases or spreadsheets, or edit large audio or video files, then a gigabyte of memory will make your computing life much easier.