I play CS ,UT,TFC,DoD and Q3 all the time with WinXP(still on 56k here ),I did have small problem with CS where it would disconnect after awhile,I read that it was a common problem with CS players & disabling QoS in the networking tab fixed the problem and it did for me.Btw I still have a Win98 PC for backup but to be honest only use it for getting updates.
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