If what Zero wrote doesn't help I have listed a few more things you can try. Most likely however, what Zero has said should fix the issue.

http://www.exchangeadmin.com/Article...ArticleID=8907

The article above discusses this in detail but it's dealing with windows NT.

Now what I would suggest you try are the following:
A.) system restore
B.) start, run, then type sfc /scannow (make sure your XP disk is handy)
C.) use the webpage above and use the utility listed on that page to boot into NT/XP and delete the pagefile, then let windows create a new one...
D.) reinstall XP but use the repair the current installation option
E.) clean format, installing XP afresh with SP1

Hope that helps,
BB

Welcome to Techzonez.