Client Laggs and wont go past Char selection after Downgrading My OS

As you kno if you read my other post, i just got win xp. I got it because i thought it would reduce lag and i could dual client for kalgas to have a rm and a DD at same time. But it backfired on me now when i start the client it stickfreezes and wont let me go in gmae only untill character selection FMC. any solutions? i tried Game booster but it doesnt help much ill try and run a system defrag and see if that works. if oyu need to kno specs of my computer just post on this topic. Thx