zombie processes in process list

[Nitin]

Hello,

I dont understand it, after some days of fine working my server starts showing zombie processes ('Z', 'T') in process list and then its impossible to reboot. Though it works ok in rescue mode, but not otherwise. I've searched a lot, but nothing seems to suit.

I'm using 7.2 and all patches are applied with up2date. It works as a web, mysql and DN server.

Any ideas...

Thanks in advance
Nitin