VanguardLH wrote:

scbs29 wrote:

Literally between switching off at night and restarting next morning I
started having problems booting up. It can take anything up to 5
or 6 tries before I succeed. This has been going on for 4 days.
There have been no changes to software or hardware for at least
3 months.

The problems can be any of :
1. Boot splash screen appears and the pc hangs. Need to switch off
power.
2. The login screen appears and the pc hangs. Need to switch off
power.
3. I log in and get bsod. I have had 3 bsod
IRQL_NOT_LESS_THAN_OR_EQUAL
MEMORY_MANAGEMENT
PFN_LIST_CORRUPT
4. I log in and the pc starts ok. After a period of time of a few
seconds or a few minutes the pc freezes. Need to switch off power.

If none of the above occurs the pc runs normally.

Following information I found on the web I tried chkdsk which
gave a clean bill of health and Win 7 memory checker which
also gave a clean bill of health.

Today I tried quite a few times to startup and eventually received a
message asking if I wanted to try a startup repair. I replied Yes.
I received a dialog stating
Startup Repair cannot repair this computer automatically
Problem signature
Problem event name StartupRepairOffline
Problem signature 01 6.1.7600.16385
Problem signature 02 6.1.7600.16385
Problem signature 03 Unknown
Problem signature 04 1549
Problem signature 05 AutoFailOver
Problem signature 06 1
Problem signature 07 NoRootCause
OS Version 6.1.7600.2.0.0.256.1
Locale ID 1033

The startup diagnosis and repair log showed no errors
except
System files integrity check and repair
Failed Error code 0x2

After this the pc booted up normally.

I have run virus checks with no problems reported.
I have also had some instances on shutdown being informed that it
was an unclean shutdown.
Also told on shutdown that there is a program stopping the
shutdown and to terminate the program before shutting down.
There is never any indication of what the program is.

Can anyone advise me ? Is the next step to boot from the
Windows 7 disk and try Repair installation ?
Should I seek professional advice ?

Packard Bell iXtreme X6620 UK
Intel Core 2 Quad Q8300 @ 2.5GHz
6 GBytes DDR2 RAM
NVIDIA GeForce GTX 750 Ti, 2Gb RAM
Windows 7 Pro, 64-bit
MoBo Packard Bell EG43M
Direct X 11

Disconnect all non-essential hardware from the PSU. For example,
disconnect all USB devices except for mouse and keyboard if those are
USB, disconnect power from the CD/DVD drive, and disconnect all hard
disks except for the one with the OS partition. The idea is to relieve
the PSU of some of its load to see if boot becomes stable. If so, time
to replace the PSU (and of a larger capacity).

Get and run memtest86+ (http://www.memtest.org/).

From online searching on "Packard Bell iXtreme X6620", apparently that
computer model came out around May 2010. That means the CMOS battery is
8 years old ... too old. Replace it. If you have customized the BIOS
settings, note them and reset the BIOS after installing the new battery
and then restore the custom BIOS settings.

Oops, forgot to mention that you might want to run:

chkdsk.exe /r drive:

I've seen where a flaky sector (within a cluster) would manage to read
okay sometimes but fail other times. /r tests all clusters (whether
allocated or not), so how long chkdsk takes to complete the task depends
on the size of the partition (the drive spec).

The problem with /r should it find an iffy sector and mark it bad and
use up a reserve sector on the disk is that it only tests sectors within
the specified partition by the drive letter. It does not test the boot
cylinder of the hard disk (where is the MBR with its partition tables,
bootstrap code, and other data, or the UEFI sector if using that). With
magnetic media, dipole stress causes reduced differential in signal
strength over time unless the sector gets rewritten. The disk's
firmware will attempt re-reads of a flaky sector, and so will the OS, so
they compound each other until it takes something like 15 attempts
before a sector is considered too flaky. There are tools that will test
every sector on a hard disk by testing a buffer area, moving data to the
buffer, and then testing the sector where was the data whether it was
within a partition, boot cylinder, or unallocated space within a
partition. The idea is to refresh every sector to ensure the dipoles
are at their maximum field strength. Spinrite is one such tool but it's
a bit dated and a bit pricey at $89. HDD Regenerator is another such
tool but every more pricey at $99. HD Sentinel has a disk reinitialize
feature in its Pro version at $30. I've heard of but not used HDAT2,
DiskFresh, and DRevitalize.

If your disk is an SDD, dipole stress is not an issue because an SSD
doesn't use magnetic media to record data. SSDs use masking to redirect
bad memory blocks to reserve blocks. When the reserve gets used up, the
SSD immediately and catastrophically fails.