As they say: it does what it says on the box:
1. Click on the "Start" button
2. Select "settings" and then click on "control panel"
3. Click on the "add/remove" programs icon
4. Select "Network Essentials" and click the "remove" button
5. Reboot your computer
(I assume you mean "what does the removal procedure do?")
Go for it. Get rid of it. XP is robust enough to stand the shock. Wonder what you thought was wrong with your system that you felt the need to download/install one of these glitzy "go faster" add-ons that only result in the kind of problem you've been experiencing.
I strongly advise clients to avoid contaminating perfectly satisfactory Operating System code with these packages.
Oh, and I strongly advise a run through with
SpyBot or similar to get rid of any Spyware that SmartPops may have left behind.