SQL Server Locks?

I have a simple web application using ASP.NET/C#/SQL Server 2000/Windows 2000

I'm having problems with the server "hanging" for ~15 minutes. Disk/CPU are idle so this isn't a resource issue. In Enterprise Manager, under "Current Activity" I see several processes waiting on:

LCK_M_X
LCK_M_S
LCK_M_S
NETWORKIO

How do I investigate this? My application is so simple, I have trouble imagining how a lock-related problem could ocurr? There is absolutely no concurrent processing done on this server. There is only one user running this app and there are no separate threads spawned.

Although this problem is sporadic, this happens the most while doing the following:

- Open connection1 (for SELECT)
- Open connection2 (for UPDATE)
- Open SqlDataReader through connection1 with SELECT statement
- Iterate through
- For certain records issue UPDATE statement via connection2.

Here are some sample code snippets. Default ADO.NET options and everything should be cleaned up through C# "using" blocks without relying on garbage collection.


using (SqlConnection selectConnection = LeadsDatabase.OpenConnection()) {
using (SqlConnection updateConnection = LeadsDatabase.OpenConnection()) {
using (SqlCommand dbCommand = new SqlCommand(sql, selectConnection)) {
using (SqlDataReader reader = dbCommand.ExecuteReader()) {
while (reader.Read()) {
using (SqlCommand updateCommand = new SqlCommand(sql, updateConnection)) {
updateCommand.ExecuteNonQuery();