declare @spid int
Declare @kill varchar (12)

create table #t (
	spid int,
	status varchar(64),
	[login] varchar(128),
	hostname varchar(128),
	blkBy varchar(32),
	dbname varchar(128),
	command varchar(128),
	cputime int,
	diskio int,
	lastbatch varchar(24),
	programname varchar(128),
	spid2 int,
	requestId int
)

insert #t
exec sp_who2

Declare c Cursor
Read_Only
For
	select	spid
	from	#t
	where	spid > 50
	and	rtrim(status) <> 'BACKGROUND'
	-- 3 hours. Change to whatever you want
	And	datediff(hour, 
			convert(smalldatetime, convert(char(4), year(getdate())) +
			left(lastbatch, 2) +
			substring(lastbatch, 4, 2) + ' ' + 
			right(lastbatch, 8)
			),
			getdate()
		) > 3
	--And	login NOT IN (Make sure to exclude the service account, replication account etc. here)
open c
fetch next from c into @spid
while @@fetch_status = 0
begin
	set @kill = 'KILL ' + convert(varchar(32), @spid)
	Exec(@kill)
	fetch next from c into @spid
end

close c
deallocate c

drop table #t