Sprint Treo 600 Locking Up

[Duhg]

Hello All,

I have a Treo 600 that recently started locking up during phone usage. If I dial a number and touch "speaker phone" it will lock momentarily and then say "no service" and then go back to main phone screen. It will also do this when receiving an incoming call. Will ring two or three times and lock up and lose the call. Occasionally it has locked up to the point of doing a soft rest to get it to work at all. Now it has started saying "no service" just sitting here when not in use. Back and forth..... service- no service. Then it may go for several hours or phone calls with no issues. I did a hard reset but no change. Phone is about a year old with version 1.2 installed. Have not had any problems at all until now. Any ideas? Thanks!