[R] computational speed question

[markleeds at verizon.net]

I have a 250 row by 20,000 column dataframe called temp and
I do

rowaverage<-function(x) rowmeans(temp[x],na.rm=TRUE )
averages<-tapply(seq(temp),names(temp),rowaverage)
averages<-do.call('cbind',averages)

, is it okay that it's been running for 4 hours or
does this mean that something went wrong. I am on windows
XP and i did ctrl alt delete and it seems like the process
is running as far as i can tell. I have 4 cpus
and the one is getting used at its max  and when
i do ctrl alt dlete task manager and click on processes
it says 699,412K under the mem usage column
but that number hasn't changed in a looong time.

when i click on performance, cpu usage says 25 % which make sense.
and pf usage sys 970 MB. physical memory total is 8387312,
available 6868916 and system cache is 3007044 but these numbers
move around slightly.

kernel memory total is 108072
paged 81344
nonpaged 26744

as far as hardware, i'm pretty clueless. all
i know is that i have 4 cpus ( actually 2 cpus but
somehow each cpu is 2 cpus whatever that means. but only one of the 4 gets used st anyone time unless i run multiple instances of R ), and 9 gig of RAM. I don't know what kind of a chip i have but i know the computer is from Dell.

it's okay if it takes this long but i was just wondering
if there is a way to check if things have stopped or
somehow frozen ?

when i do a tail on the .Rout file ( I am running the program
using R CMD BATCH ), it's just sitting at the same spot
where this computation would be done so I can't tell much from that.
Thanks.