Laptop wifi problem

Any ideas on this problem? I have an IBM Lenovo T60 laptop that was working perfectly over wifi. Then I changed location and now it wont connect to any wifi at all! Nothing has changed software wise and the laptop can see the wifi signals but when I try to connect I get a message about being out of range. Have reinstalled the wifi drivers, checked for hardware changes, checked for disk errors, and can run an internal ping. Running on XP, any ideas much appreciated as I really dont want to reinstall XP again!

Last year, a friend couldn't connect to my wifi. I know it wasn't a range problem.

He assumed it was he didn't install Service Pack 3. I took the password off the router and he connected OK.

SP3 might be worth a try as my travel companions laptop connects fine to the same wifi point and has SP3 while mine is SP2.

Yippee!! Upgraded to XP SP3 and now connects fine! Thanks for the idea misterbee, should have thought of that one myself!