The messages began "The description for Event ID 2 from source PHP-5.2.4 cannot be found." so OK, not DELL but installed by DELL and these messages indicate that its garbage anyway otherwise it would have registered itself correctly.
Some examples of the actual messages (20/min):
- The text of the event was "php[6732] gets Content-Type: text/vnd.wap.wml; charset=utf-8
- PHP Warning: Cannot modify header information - headers already sent by (output started at C:\Program Files (x86)\Common Files\Dell\apache\htdocs\media_tags.php:0) in C:\Program Files (x86)\Common Files\Dell\apache\htdocs\dsl\include\mob_header.inc on line 0
Anyway, glad thats over, will look at the others when they give me a reason. Hopefully that also removes the occassional 2-5 second hang that I get where even mouse doesn't move (in Vista Ultimate 64 bit).