What is up with My Virgin Connection?

[Kam_voo]

This is rather Hard to explain ,but i'll have a crack at it.

When I got a Modem for my computer the internet connection was perfect. Then some guy come around installs aload of crappy virus protecters and a 'Belkin Wireless G Router' Now the connection still works but its really bad I can't stay logged into msn For it keeps logging me out for 'lost connection'. i tried to put the modem back on its own but the internet stops working completely. I tried rebooting the computer but i turns out all my reboot points have been lost. Is there anything i can do? to Get either the Modem to work on its own OR the 'Wireless router to work with the same connection i had before i got it. I'm not sure if its anything to do with Virgin (NTL).

Thanks for the Help I really appreciate any Useful information.