MadMonkey:

My post is too late, but this might help in the future. It might also help those who have similar problems.

I have seen several similar problems before. Prior to running and reinstalling the OS, there are checks that you can do to see if there is harware damage.

There are three main reasons why this could be happening: a faulty CPU, damaged RAM or a damaged hard drive. This are usually the result of overheating, exposure to magnetic fields or physical damage (e.g.: dropping the laptop).

The BIOS chip is fine because it boots up and it lets you go into the BIOS settings screen.

The CPU is probably OK because it is letting you boot up and it lets you start the Windows boot sequence. However, it is still possible that the CPU is damaged. Go online and do a search for something like "CPU diagnostic software" or "CPU diagnostic freeware". I can recommend that you try these ones:

http://www.diagnoseprogramm.de/
http://www.binarica.com/downloads.html

or something similar. Then run a diagnostic on the CPU and other hardware. Binarica has tools for checking RAM chips and other hardware components. These tolls might not necessarily be adequate, so search for others in case these don't give you what you need.

The RAM could be a problem. Sometimes faulty RAM causes either a failure to boot, or a failure to load the OS. You can check the RAM chip if the BIOS Settings allows for a "memory check after boot up". You need to find this in the BIOS settings. If you cannot find it, you can go to the laptop manufacturer's website and find the motherboard manufacturer and model. The manufacturer of the motherboard will have online a user manual and tools for diagnosing problems with the hardware and for updating the BIOS. Check the BIOS version and determine whether you need to flash the new version into the BIOS. You need to do a memory test of the RAM chip, it is as simple as that. The Binarica site has a program called Gold Memory. That can test the RAM too.

The hard drive is my number one candidate here. To check and repair the hard drive you need to know the manufacturer and the model number. Go into BIOS and find who makes the hard drive. Go to the manufacturer website and in their dowloads section you will find diagnostic and repair tools for the hard drive. For example, Seagate had a program called SeaTools. That will do extensive tests of hard drives and reformat harddrives if necessary.

Other components can cause trouble too, like the video card. Again, a search of the manufacturer's site will give you tools for diagnostics. Most manufacturers of hardware components have diagnostic tools that are necessary for quality control. They release those tools to the public so people can troubleshoot problems with the computer. I recommend that you check as many hardware components as possible before you decide that the only solution is erasing the hard drive and doing a clean Windows install.

Once all hardware is checked, you can proceed to try to repair windows. The first step is to attempt to boot into DOS. You said that you can go into Safe Mode. Try to go into DOS with Safe Mode. Once you make it there run a program called CHKDSK. Simply type that in DOS and press enter. It will check the file structure in the disk and let you know if there are damaged files or folders. The program will attempt to repair some fo these problems.

If CHKDSK does not give you anything, you insert the Windows installation disk and try a windows "repair". Sometimes repairs work, sometimes they don't If something was wrong with Windows, usualy the rapair sequence will tell you what the problem was. If the repair fails then the only option is a clean install and that means wiping out the hard drive and reinstalling the OS in full.

Prior to doing that, you will need to decide if it is worth getting useful data back. That can be tricky and your first option is installing a new hard drive and putting windows in it, then accessing the data in the old hard drive. The second option is going to a professional who can extract all the data for you. It all depends on how you want to get that data back. I find that buying a new hard drive is often the cheaper of the two options.

If you decide to wipe the hard drive and reinstall the OS in full, I recommend a full wiping of the disk. You can use the manufacturer's program (e.g.: SeaTools), or a Free Dos CD, then useing commands like FDISK and FORMAT. In FDISK you would need to delete all partitions and then create a primary DOS partition using the entire hard drive. Once that is done, you can format with something like this:

format c: /u /d

That is a full unconditional format with verbose output, so you cn see every detail of the formatting process. This can take several hours to do, so start it in the evening and leave it running all night!

For Free DOS go to:

http://www.freedos.org/