Just wanted to share some information for anyone else having a certain boot problem related to atipcie.sys. Pauli pointed me in the right direction in another thread. Apparently, this problem is not uncommon. Atipcie.sys is one of the drivers associated with ATI video hardware.
Symptoms: In a normal boot, it gets as far as the Windows logo and then hangs. Booting in safe mode, the last driver displayed before the system hangs is atipcie.sys. You may also see some lines flash on the screen before the boot loading starts displaying.
It is not clear whether the problem can be just a bad driver or if it's the ATI driver getting indigestion because of a problem with the video hardware. If you see lines flashing on the screen at the very beginning of startup, that's not normal and probably indicates an underlying hardware problem. More than one beep when the computer first starts up, particularly 4 or 5 beeps, indicates that you probably have a problem with the motherboard. You won't necessarily get the diagnostic beeps, though.
If you have an underlying hardware problem, it will not get better but you may be able to continue to operate for a long time without the problem getting worse. Just have a plan B and expect that sooner or later you will have to bite the bullet. If the underlying problem is a bad motherboard, you may run into Windows licensing issues if you replace it. My own plan is just to buy a bare bones shell (case, power supply, motherboard, and new hard disk with Windows already on it), and move everything else from the old box.
Many people reported fixing the boot issue by replacing atipcie.sys. That is definitely a solution if the problem is a bad driver and may also work if the problem is the driver not liking a hardware problem. This driver is part of the Catalyst suite and the Internet is full of discussion about people having problems with Catalyst components in general. Many people just uninstall the whole Catalyst package. I don't know what driver replaces it in that case. There might be a generic Windows driver that is part of the Windows package that gets loaded if you remove Catalyst. If you want to go that route, do some research.
If you want to experiment with replacing the driver, make sure you have an alternate way of booting the computer. There are various ways to create a CD or DVD that will let you boot up externally in a state resembling safe mode and give you access to a command prompt and sometimes various repair tools.
Another is to create a Linux boot disk. Most Linux distributions work by having you create a "trial" DVD, which you use to boot up in Linux and try it before you install it permanently. You have full access to the features without installing it on your system but be aware that everything you do is done in "virtual space" that disappears when you reboot (changes you make to C: don't disappear). The Linux file manager will let you play around with the driver files on C: (rename, copy, etc.). Linux uses a different video driver and, at least on my machine, didn't have a problem with the motherboard hardware issue.
In my case, I renamed atipcie.sys to atipcieOLD.sys (it is in /Windows/System32/Drivers), and replaced it with a file I downloaded. This is generally not a good idea. Most of these sorts of drivers are part of a package and you may encounter problems if the file you download is not the same version. There are also plenty of shady sources on the Internet that prey on desperate computer owners who receive a virus as their download. Most other driver download sites are just selling driver "maintenance" software that will find all of your driver problems and fix them for you. I'm not aware of one that will not get it wrong for more drivers than it fixes. I downloaded the driver from
http://sysfiles-download.com/sysindex/AtiPcie.sys.html . This is a reputable site in terms of just downloading a legit, virus-free driver file. There is no guarantee that the file you get is the version you need, the site does not provide much in the way of information about each driver; you just have to try it. The site has a huge collection of driver files, available free. The driver I got was exactly the same size as what was in my machine (always a good sign), but a newer version (ver 1.3.2.54).
The replacement driver was only a partial fix on my machine. For reasons that escape me, I discovered that the machine will boot with a good Windows driver if I disconnect all external hard disks until after startup. My old driver worked that way for a while and then wouldn't work at all. The replacement driver functions properly and will allow Windows to boot with no external drives. I have no idea why disconnecting external drives should affect a video-related problem, but it is something else to try on your machine. Bottom line, if the underlying problem is hardware, there is only so far you can go fixing it with software.