pc startup problem

[janefield]

When I come to start my PC more often than not this message appears:
"No OS found. Please insert OS disc and press any key." I was too wary
of inserting the recovery disc supplied by the shop that assembled the PC.
Instead I pressed any key and found that by pressing any key three times
Windows (XP Pro Service Pack 3) would start normally. The shop were puzzled
that this should be happening. Other error messages have started to appear.
One refers to a missing or corrupt Win32 file, hal.dll and I am asked to re-install
a copy of it. Another message says: "A disk read error occurred. Press Ctrl+Alt+
Del." Nothing happens when I do so other than the same message appears over
and over again. On each occasion that Windows would not start I switched off the
PC and left it for a while and lo and behold it started after just a few winks of a cursor.
Can anyone please tell me what is causing this? The last time I was at the shop
showing them on my camera the hal.dll message I was advised to use the recovery
disc to repair Windows, but on inserting it I did not see the word repair anywhere
and did not want to risk losing my data. So I would appreciate any advice before
contacting the shop again. The PC is only a month or so old.

[Soopafresh]

Whatever it is, back up your data if you have anything important on the drive. Get one of those external USB hard drives if need be.

You could have a physically bad drive (requiring replacement) or a virus

Unlikely, but worth a look is this:

"There have been a number of complaints from owners of large Seagate drives recently. These drives all have one symptom in common. During a power up the drive will seems to disappear. The drive is no longer detected by the PC and does not show at the POST (Bootup) screen or in the BIOS. This problem was first reported with new Seagate 1.0 and 1.5 Terabyte drives, but as more Seagate customers have come forward it appears that the problem is affecting drives from 500gb and up. The affected product lines are:
Barracuda 7200.11
DiamondMax 22
Barracuda ES.2 SATA
SV35"

http://blog.techfun.org/do-you-have-a-seagate-brick

[Nelson37]

The key here is the variable nature of the problem. If you have a corrupt file, it is ALWAYS corrupt. You are getting loss of drive function at various stages.

Try taking off the case cover and you may very well actually hear the drive spinning up repeatedly.

You should also check data and power cables and exchange if possible.

Very likely a drive getting ready to fail, possibly power supply or mobo controller.

[ntscuser]

Ditto here. Bios kept telling me a crucial boot file was missing when I knew for a fact there were at least two copies on different drives. Turned out to be early warning of eventual failure of a Seagate system drive. Had to physically disconnect it to allow the other drive to boot.