I have to say mine is also doing the same it's pissing me off! should I replace it or get a 722k? Also did it extend your contract?
If you are referring to the 612, I had 3 and everyone locked up in fast forward.
The 722k doesn't have the over the air (OTA) connectors or an S-video output. If You don't need these, I would demand a 722k.
It will not cost more, except it will extend the 2 year commitment. For me that was only an extra month.
The 722 is a really nice box so far. It has a large hard drive and several more features that the 612 didn't have.
Every one that has a 612 locking up should demand a 722.