Vacuum Problem

Hi all!
I do have postgres 6.3 running on Redhat 5.0, pentium 166 with 32MB and
100MB swap.
Recently I copied delimited files that contained about 40,000 rows to
three different tables. Once I had to drop the table also. Then I
created another table with those three tables. Each table has 10-15
fields of text,int,floate and datetime types.

Finally I ran vacuum from psql.

It is running for last two days. CPU% started from 45% and slowly
getting close 100%. This afternoon it was
83%. on ps command Status ~> R and Timer counter runs..

Till this afternoon I had a access to tables through another tty. I
lost that this afternoon and when try psql foo, session hangs.
Can I kill the vacuum?

Any ideas are higly appriciated.

Anil