there are several things that make it freez.
1.The browser not stable anymore.
soolution- repair it by unistall, and install it.
2.your computer need mantainance.
go to start>all programs>accecories>system tools>
and you will see many utilities there, do disk clean up and disk defragmenter.
3 - virus.
you need antivirus to because sometimes virus make your cmputer freez. if you have one you might want to unistall it and get other antivirus.
suggestion: bitdefender, kaspersky, mcafee, avira, if you dont have much money to but it download the trial version and it help.
4 - your windows is not stable.
solution-2
1.system restore - you can make system restore to restore your laptop to the time where your computer didn,t freez. to done this read my post at my blog
http://laptop-driver.blogspot.com/2008/09/system-restore.html2.or--this is little bit advance - if you have win xp cd, insert it and resart, press any key when asked, press enter when asked, press f8 to terms and license agrement and after that press r to repair. let it do the work, please remember this is advance option and during the repair process it will ask you for the cd key of the cd