Vista Spooler.xml

I was working away on my less than year old Vista PC with a 250 Gig hard drive when Windows tells me the disk is getting full! Windows is all like 'disk cleanup' and 'remove some programs'. Serious! Was it the VS2008 I just installed? No.
I used Silurian DiskSpaceChart to find out where all my disk was going. That's a typical disk usage pie chart thing that puts itself in the right menu. You can drill down through the large folders to find the large file. It's OK. It was the first thing I found for Vista.
So what I found was something writing continuously to C:/Windows/system32/spool/spooler.xml, at like 300 MB per minute! I tried to find out who was writing the file. Resource Monitor helpfully identified 'system'. Thanks. I didn't have SysInternals Process Monitor installed, and I didn't want to try while the machine was so sick, so I couldn't get any details on who was doing all that writing.
I rebooted into safe mode and deleted the file.
When I booted back the file was 33k and stayed that way. I think the file is a printer log and the problem is either my HP printer drivers for the 3390 or MS XPS. I recall running WireShark and seeing every machine with those 3390 drivers polling the printer status over the LAN every millisecond.