How many times have you tried to downolad more than two files at the same time using Internet Explorer? You are right, it´s not possible, by default, two is the limit for simoultaneous downlad sessions.
Using this key you will be able to break this limitation setting the limit to the value you desire.
The registry path to modify is this one :
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Explorer
Below this path there are three entries (DWord Values) we have to set :
MaxConnectionsPer1_0Server : Number of simultaneous sessions you want to configure, i.e, 6
MaxConnectionsPerServer : Same than above, number of simultaneous sessions you want to configure, i.e, 6

One more time we have to choose between security and functionality.
Using this key we have the possibility to make automatic logon in our XP Workstation when the workstation is started. This solution some times is mandatory when some process in the machine needs to run into the logon environment of some user, it means, an application that can´t be installed as a service.
But this is a security breach as the information about logon name and password is stored in clear text in the registry.
The registry path to modify is this one :
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\Winlogon
Below this path there are three entries (String Values) we have to set :
DefaultUserName : “logon name of the user to make logon”
DefaultPassword : “password for such user”
AutoAdminLogon : “put this value to 1″

You can find here programs that automatically starts when Windows Start. These are not the same programs that are included in Startup programs group.
Tipically, program icons that you can see into the task bar (bottom left in your desktop) are located in this registry key. This entry is commonly used for programs that you install and are autoconfigured to autostart without your approval.
It´s healthy to take a look regularly to this key because is used by viruses, internet explorer adins, spyware, …
You can find it in the registry path :
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

As usual with these kind of parameters, you can improve the performance of your machine but losing “security”. Pagefile.sys may contain sensitive information like passwords, web browsers cookies, … that many people prefer to delete to not beeing available after restart the machine.
If security in this topic is not your concern you can boost the start-up process of your machine not deleting pagefile.sys when you shutdown your machine.
To disable pagefile clearnig at shutdown this is the key that you have to set to “1″ :
ClearPageFileAtShutdown
You can find it in the registry path :
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management