I had similar problemms when testing MS SQL Server 6.5. What I found in reviewing the memory usage during updates and inserts that MS SQL Server was not releasing the memory. This resulted in a continual slowdown of the processes and lock up of the system. Then a re-boot of the system was required to release the memory. Because it was a memory leak (just a guess on my part) closing down MS SQL did not free up the memory. Since then I have tested and purchased ORACLE. This does have any memory leaks will stay a flat line during the processes I have tested and I have not re-boot the computer for weeks.