disk drive maker sandisk fell more than 5% on heavier than usual volume. there was no corporate news today, but sandisk shares have dropped to their lowest price since april. cisco systems was the biggest percentage loser among dow components, falling more than 2%. cisco's latest sell-off began three weeks ago when its quarterly revenue came in a fraction below analyst estimates. this is a new 52-week low for c-s-c-o. intel also weighed on the dow, and also falling to a new 52-week low. the company is in the process of buying software security company mcafee, and reports tonight indicate it is close to a deal to buy the wireless business of german semiconductor maker infineon. and speaking of computer security, look at this rally in arcsight. it rocketed higher by 30% on almost 20 times its usual volume. earlier this week on our "word on the street" segment, james rogers from thestreet.com, highlighted arc as a company analysts see as a buyout target. "the wall street journal" quoted sources as saying the company has been shopping itself around to possible