Well Im pretty sure that Most Wireless Mice and keyboards use BlueTooth or IR, But if they do indeed are wireless and operate at the same frequency as your wireless ROuter and Card, then its possible.
(Or is Bluetooth the same As Wireless, hrmm well I guess Ill find out soon enough.
Give us the specifications your Wireless Router, Keyboard, Mouse and Wireless Card.
Has this always happened? How long have you owned the computer for?
Are there any microwaves or Wireless Phones close to your PC or Wireless router?