[Grammar] If it hadn't been for your help VS If it weren't for your help

[lagoo]

Hi,

Here are the two confusing sentences:

1. If it weren't for your help, we would be in serious trouble.
2. If it hadn't been for your help, we would have been in serious trouble.

Has someone already helped us or is helping us in #1?
If someone has already helped us, why can't say "If it hadn't been for your help, we would be in serious trouble" as used in #2?

 

[GoesStation]

In number 1, the assistance is in the present or the recent past and the trouble is happening now. In number 2, both are in the past.

 

[lagoo]

So I guess the structures are:
1. If it were not for..., we would...
2. If it hadn't been for..., we would have...

Is there any mixed structure like "If it hadn't bee for..., we would..."?

 

[Matthew Wai]

'If it hadn't been for your help, we would be dead now.'

I think it is a mixed conditional.