I can't take this anymore

[Reach]

im gonna stop playing this fucking game if i can't fix this problem.

ever since i got xp, no matter what i do, i cannot get sm to run properly. it lags constantly, and its nearly impossible to play hard songs. the arrows are jerking around and shit, my timing is terrible and it hurts my eyes just looking at the screen because of the way it lags.

And it didn't lag like this on 98, plus i hae a new hard drive and my pc runs 10x better in general...

so yea...does anyone know what could be causing this? x__x a problem with xp? is there a way to fix it? because it shouldn't be lagging with nothing running, this is just retarded.

btw all my graphics options are like...on the lowest possible aswell k...thanks