problem with Mitsubishi projection tv

Bought Mitsubishi WS-65807 tv in 2001.  A year or two ago we started to notice whenever we turned the tv on the colors and the picture, on the outer edges of the picture (on both sides) were separate, and arc'd. It seems to correct itself after it has warmed up. Sometimes that takes a few minutes or a few hours. Can anyone help us with this problem? Thanx