Windows 7 - 64 bits - Delphi 2007

Hello! I know that this is probably not a Delphi issue, but I ask, just 
in case... perhaps someone had a similar problem...

I use D2007, Firebird 2.5 and IBX components, and ClientDatasets (I know 
IBX doesn't support FB, but I just use it in a very simple way, so 
there's no problem with that - I think)

A customer of mine has this problem: Using Windows 7 64 bits, when he 
deletes a record in a table the PC hungs completely. The mouse, the 
keyboard... everything. He has to turn the PC off.

I'm sorry I have not more details about the problem. The question is: is 
there any known issue which can "kill" the PC in such manner?

Thanks for any help!!!

Sergio.