> What would be the recommended DefaultDbCachePages (or Buffers) values
> to use in the following situation?

...

> Having recent performance issues. A number of new processes from a
> third party are accessing the main database plus MSSQL Server (using
> 152MB memory)/Javaw/backup (be*.exe) services are installed but have
> been there for quite some time 'without any problems'.
>
> Swept, Validated ok, backed up and restored but system is crawling and
> this is now a big problem. Any ideas anyone?

If it was that easy and all performance issues could be solved by setting number of buffers :)
You can try to tune number of buffers yourself to get better performance,
but it is unlikely that it will solve situation described like "system is crawling"
and "big problem". You have to identify the main reason of the slowness first
(stuck transactions, committing every single operation, badly optimized
queries, too much/too few indexes, unexpected side effects of triggers, ...)

Ivan