Can computer cause interference with monitor?

[Illegal Alien]

I have a desktop computer with monitor on top. On the bottom right of the screen i get somekind of wavey/pulsey thing going on. Could anything in the computer interfere with the monitor? I think that specific corner of the monitor is over my CD-ROM drive and hard-drive. The interference doesn't happen when monitor is taken off.

[sns]

It appears that it is in this case. I would have thought the pwr supply would have been the problem. Does it do it all the time?
My old pc would affect the tv if I left the cover off and the h/drive would wake up and start to spin up. It would only cause a little bit of interference for about 3-5 seconds then clear up. Never the monitor though.
Anyway my new system doesnt seem to have the same affect so I just assumed my shielding is a little better in this particular set up of CD's & h/drives.
Does it get any better if you put a phone book underneath or do you have to move the monitor as far as possible from the case?

[DemonKnight]

Sounds like somthing close to that corner is slightly maganitized. I had a modem once that would cause static on the TV down stairs every time it dialed out.