On Sun, 24 Jun 2007 22:50:11 +0100, "Keith French"
I have WinXP SP2 and every so often when clicking on the Start bar, nothing
happens. Then I find that although the mouse cursor moves fine, nothing else
works except CTRL ALT DEL. When I look in the task list nothing reports as
not responding.
OK - this looks like a common failure pattern. Qs:
- move mouse; OK... but does it stick at all?
- move mouse over window edges; does pointer state change?
- press NumLock key; does keyboard LED change? Immediately?
- is HD activity LED on, i.e. is it:
- randomly flickering, random seek noises
- constant on, no seek noises (sector retry?)
- constant on, periodic seek noises (cylinder servo retry?)
- constant off?
- is Ethernet LED active, indicating traffic or "bad cable"?
- any change if you eject CD or unplug any peripheral?
- immediate, delayed, or no response to these keys:
- Alt+Tab
- Ctl+Esc
- Alt+F4
- Ctl+Alt+Del
- Ctl+Alt+Del shows task manager OK, so...
- if Idle = 90+, you are waiting for something other than CPU
- if Idle < 50, you are waiting for CPU, as hogged by something
- does short press on ATX power off initiate orderly shutdown?
- does long hold on ATX power off initiate bad-exit "power off"?
- does a press of Reset button initiate immediate bad-exit reset?
Low-level services and device driver code may disable interrupts for
critical sections that are supposed to complete quickly. If these bog
down, e.g. waiting for internal LAN packet or HD sector retries, then
no software thing can break through, so the mouse pointer movement
will generally stop, and task manager won't appear (or be updated)
until control returns from the code.
Sometimes software may wait for a device, but at a higher level, so
that interrupts are enabled. There's nothing to do until the awaited
condition is met, so the CPU sits in the idle loop.
Modern HDs and optical drives operate in UDMA modes, such that the
processor is not involved in the mechanics. In this case, a system
that is waiting for HD etc. will not use CPU; CPU will be idle.
If "too many" UDMA errors are detected, then HD or optical drives fall
into PIO mode, where the CPU has to be involved. In such cases, you
may see CPU usage when these devices are busy, either with normal but
bulky operations (e.g. an av that's "scanning everything") or with
small operations that are bogged down with bad disk retries.
I have tried updating the video driver and it is still the same. I have also
run a virus scan and a hard disk error scan all of which is OK.
I'd do this, with each step as additive:
- normal Windows as-is (known to fail; repro?)
- as above, but unplug LAN and disable WiFi, IR, BlueTooth
- as above, but disconnect all peripherals
- as above, but eject all removable disks
- as above, but disable all non-MS services in MSConfig
- as above, but disable all startups in MSConfig
- as above, but F8 "Plain VGA" boot
- as above, but F8 "Safe Mode" boot
- as above, but F8 "Safe Mode Command Only" boot
- as above, but non-HD boot e.g. Bart PE CDR
That's test-to-fix logic, but in practice, I'd work in reverse on a
test-to-break basis, i.e.
- non-HD boot e.g. Bart PE CDR, check HD, do formal av
- F8 "Safe Mode Command Only" boot, additional anti-malware
- F8 "Safe Mode" invokes shell; Nirsoft Shell Extensions Viewer
- from Safe Mode, apply MSConfig suppressions, then...
- Windows boot, OK?
- Windows boot with all services enabled in MSConfig, OK?
- Windows boot with all startups enabled in MSConfig, OK?
- ensure firewall is on, connect LAN
- check settings safety, enable WiFi, Bluetooth, IR
- reconnect peripherals
- add back removable disks, after av-scanning them
Another "dimension" to explore, if applicable, is different user
accounts. That can pin it down to that account's settings etc.
--------------- ----- ---- --- -- - - -
Tech Support: The guys who follow the
'Parade of New Products' with a shovel.
