I am trying to unistall the AVG Antivirus free version but it is not getting uninstalled.
These are the following details which occur when I try to uninstall this software::

Local machine: installation failed
Initialization:
Error: Checking of state of the item registry key HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run failed.
Insufficient system resources exist to complete the requested service. (1450)


How should I remove it? :(

Huh.. that's odd.
Maybe you just ran out of RAM?
Try restarting the PC and have another go.
If that doesn't work, use a registry cleaner (try CC Cleaner - free download).

You could use a brute-force uninstaller program, but I think it would be better to try and remove it the proper way.