Q: I have Seagate Barracuda 7.7200 40Gb, when i scan it in mhdd almost all surface looks perfect, but drive have 1 bad block(or little bit more) in first sectors. What i can do with this drive to fix the problem?
A:First rule: if data is important you must save it first, before do any "repair" or you can loose you data in this drive at any moment.
Now, then data saved we can start drive diagnostic. If drive have few bad blocks we can divide situation to the following case:
Universal:
a) software bads - this is actually not bads, but sectors with incorrect ECC info, simply rewrite sectors to remove trouble.(MHDD erase waits will help)
b) actual bads - well sometimes surface can be worn and we have actual bads. If we have not very much bads that we can try remap them. Try simple rewrite bad sector ( most drives perform remap on write ) or use mhdd remap on etc. ( then bad sector remapped SMART Reallocated sector count attibute increased )
Seagate 7.7200:
c) head problem - drive firmware detect head problem and switch to "read only" mode. This can be diagnosed by following symptoms:
1. after drive power on, it take long time to become ready (BSY status cleared)
2. drive don't write

if you run mhdd "erase" (not fast erase, but normal erase) everithing stopped after mhdd write 765 sectors. (really nothing writed at all, if you try writing disk sectors with diskeditor, you see what nothing changed)
Such troubles most likely can't be fixed, because they caused by bad head
We can "enable" write for such drive, but it died again quickly...