Does it happen at regular intervals, specific times?

Perhaps some program is inserting/retrieving lots of fresh data or using not everyday queries?

Buffer cache hit ratio is related to memory.

Might be completely unrelated, but when a particular printer mentioned an error it caused to block all tcp/ip sockets, resulting  in communication link failures, no internet ...

A thing that helped was...

What processors are there in your Dell system?

It could be hyperthreading (like Pentium 4 does)

If I read this correctly

H1 gives a list of products identified by species.ID and producttype

D1,D2... gives the amount of a specific size

and you want it presented in 1 line species...

You can implement the log shipping using sql-scripts

Backup database 1, restore to other in Standby mode (with standby or normally)

Backup log database 1, restore to other (with standby or no recovery)

Backup...

1) Why aren't you using

AND pb.SalesText like 'A%'

instead of

CONTAINS(pb.SalesText, 'A*') ORDER BY SalesText, VendorName

No need for the fulltext indexing and uses a regular...

Depends on what Access version you are using since the more recent ones work with MSDE (slimmed down sql server). In this case they have the same query syntax.

1) The...

the auto close option of the database is on?

IIS en SQL SERVER on the same machine?

Is is possible to put IIS on one machine and SQL Server on another?

How is the authentication to sql server set up?

Windows authentication or sql authentication.

do you log in using Windows authentication or sql authentication?

Be sure your idenitity fields are still identity fields, also your timestamp fields.

Any recent changes (new programs,...) that could coincide with the start of the occurances?

Could be a permission problem. You have no problem running it under the sql server agent account?

You can script out the jobs, by rightclicking the job and chose All Task -> generate script.