There isn't a lot of memory installed, especially if you're using XP. A memory upgrade is possibly needed. What operating system is it using? A reinstall of Windows would also speed things up if you had the Restore CDs or a full Windows disk. If the slowdown is a recent thing, a scan for viruses, spyware, malware etc. might be a good idea. A general cleanup of files and a defrag of the hard drive wouldn't do any harm either.