Why has a bizarre grid pattern attached itself to my cursor??

[Tim Monks]

We have a rather ancient 4D50G machine (hinv details below)
	1 12 MHZ IP4 Processor
	FPU: MIPS R2010 VLSI Floating Point Chip Revision: 2.0
	CPU: MIPS R2000 Processor Chip Revision: 5.0
	Data cache size: 32 Kbytes
	Instruction cache size: 64 Kbytes
	Main memory size: 16 Mbytes
	ENP-10 Ethernet controller 1, firmware version 4 (SGI)
	ENP-10 Ethernet controller 0, firmware version 0 (CMC)
	Graphics option installed
	Interphase 3201 2-drive ESDI disk controller 0
	ESDI Disk drive: unit 1 on Interphase controller 0
	ESDI Disk drive: unit 0 on Interphase controller 0
	Integral SCSI controller 0: Version WD33C93

Yesterday the machine had to be rebooted, and when it came back up, no
errors in SYSLOG, the arrow cursor now had an acompanying little grid 
pattern sitting on its shoulder (6 vertical red lines + some white 
dots in ~50x50 pixel square). 

Bizarre :-<

It doesn't stop there. I have a program using crosshair cursor.  This
now comes up as a series of 10 or so cursors all offset from the 
correct position. - unusable !

As this machine is our gateway to the world I don't want to take it
down to run diagnostics if I can avoid it.

Do these symptoms sound familiar to anyone ???


Thanks.
--
Dr Tim Monks                                
Image Processing & Data Analysis Group | (direct)   (+61-3)566-7448
BHP Research - Melbourne Laboratories  | (switch)   (+61-3)560-7066
245 Wellington Rd, Mulgrave, 3170,     | (fax)      (+61-3)561-6709
AUSTRALIA                              | (internet) tim at resmel.bhp.com.au