Gator - let me take a stab at this.
When your computer fails to boot into "protected mode" (but will boot into 'safe' mode) one of two things could have happened; a hardware failure (less likely) or an OS corruption (quite likely). If the OS is corrupted, it's pretty important to figure out why, so it can be prevented. If a memory stick or the hard drive are flaky, they can prevent the computer from loading the protected mode drivers or in some cases, from booting at all. You can get a good feel for what's going on with a couple of free utilities.
For the memory, download
Memtest86+. This will create a floppy you boot from and will run some pattern tests on all your memory. Let it run all night. In the AM, "No Errors" is the right answer. You'd be surprised how often computers come to me with a rototilled hard drive and RAM that's flakey. Windows caches a ton of stuff to RAM during hard drive writes, so if the memory generates errors, the data gets more and more and more corrupt until something happens. Very often, it's exactly what you are seeing. So, this is a good place to start.
Next, make sure the hard drive is working as it should. All the major hard drive manufacturers (Seagate, Hitichi, Western Digital, etc.) all have free non-destructive diagnostic tools available on their web sites so visit the site for the brand you have, download their diagnostic tool, and see what you find there.
If either of these tests show issues, that issue really needs to be addressed before you go any further.
If the hardware comes back "clean", you may have to re-install Windows to get things working. This can be a "brute force" install if there's nothing on the drive you care about saving, or can be done with a bit more finesse if there are documents on the drive you really want. Another option if your current drive is loaded with documents you want to save is to buy a new hard drive (cheap these days), install the OS on the new drive, then copy your files off the old drive and re-format it to use as storage. Lots of options here....
It could be a virus. Do you have anti-virus software installed on the machine? Is it up to date and working..??
I'll try to keep an eye on the therad but please feel free to PM me if you want more help.
Good Luck - B.B.S.
