Need help - upgraded Series3 and now it locks up periodically

Recently I (finally) upgraded my old Series 3 TiVo by replacing the stock drive with a 1Tb drive (WD AV-GP WD10EURS), and using WinMFS to copy everything from the original drive to it, and it seemed like it worked - except for one thing: now the TiVo (which has always been very reliable) is now locking up occasionally (about once every week or two).



I can fix the problem by simply unplugging the TiVo and plugging it back in, and it's good for awhile.





Any ideas what I can do? Could it be a bad hard drive (that I'd need to look into doing a return/exchange)? Or just bad sectors that I could do something so that TiVo doesn't attempt to read/write those sectors?





Thanks!