[dba-SQLServer] SQL Server "locks up"

Why does SQL Server "lock up" when I am running a query and I try to do something such as view the 
design of a view on a completely different view?

BTW SQL Server has been limited to 5 gigs out of 8 gigs total memory.

It seems that SQL Server should be able to do things like this with absolutely no hesitation.  Yet 
when I am running a large query and I try to do anything else, such as view the tables or views, 
view the SQL in a stored procedure etc., even in a completely different database, the entire system 
just locks up for a long time, as in a minute.  The odd part is that the query isn't even using much 
cpu.  I have a quad core and the total cpu usage in task manager says 0%, yet I can't get anything 
else to work.  Even something like saving a change to an Access module and closing Access takes a 
full minute.

It is truly annoying.  I often have to do other things on the machine while queries run and it is 
just impossible to get anything else done.

-- 
John W. Colby
www.ColbyConsulting.com