Developing strategies...Plan A and Plan B
There are several ways to approach this problem, and most of them involve using of an Emergency Start-up Disk (ESD). I will assume you have one, or can make one from someone else's WINME setup.
Here's a practical RULE OF THUMB that works about 90% of the time:
If you can force an ESD to boot to a DOS prompt, and you can access all of your drives, you most likely have a software problem, and *NOT* a hardware problem. This is often a *HUGE* time saver in troubleshooting, but there are a few important exceptions: (a) intermittent PSU voltage fluxes, (b) occasional lockups due to over-heating and air-flow, (c) a totally fried ISA/PCI card such as sound, modem, NIC. However, these exceptions are relatively unlikely, and probably do not apply in your situation. The rule of thumb usually works because software fails far more often than hardware.
The overall, big-picture strategy includes Plan A and Plan B. Plan A assumes you know some basic DOS commands, which you probably do. Plan B assumes you are comfortable working inside your case, which you probably are.
PLAN A STRATEGY: Force a normal or SAFE mode boot (if possible) and check the Device Manager for resource conflicts. If you find them, disable the offending hardware/driver and reboot. Then reinstall the driver or get rid of the hardware.
PLAN B STRATEGY: If plan A fails, open your case and start pulling out cards, one at a time, beginning with the last one installed. After each pull, try to reboot. You may have to pull everything except the video card (if you have one). However, if you have a virus or funky start-up software, Plan A or B will not help until you dump them.
PLAN A: Insert your ESD and boot to the start-up menu. Start your computer WITHOUT CD-ROM support. (First, you won’t need your CD drive, and second, your CD drivers might interfere with this process.) Boot to the A:\> command prompt. Switch to the root directory of the HD with the active partition, if possible. This is usually C:\> (If this fails, go to PLAN B.)
OPENING ATTACK: ATTEMPT TO RESTORE REGISTRY AND NORMAL BOOT
You are at C:\>. You are going to use the scanreg.exe utility to restore the registry. By default, you should have 4 or 5 compressed backups of your registry with file names like rb001.cab up to rb004.cab.
1) You need to find the scanreg.exe file, which is usually located in C:\Windows\Command.
2) Switch to the directory with scanreg.exe and type scanreg to launch the utility.
3) When the utility launches, you'll see a gray on blue screen with 2 buttons.
4) Select the button that says "Start."
5) On the next screen, choose "View Backups". Next you will see a list of .cab files.
6) Choose the most recent backup that says "Started" in the left column.
7) Choose the "Restore" button.
8) Take your ESD out of the floppy drive.
9) Choose the "Restart" button.
If the registry restore works, you should get a normal boot into WINME, perhaps with a few error messages and attempts to detect hardware. You may not have to deal with SAFE mode at all. Cancel any hardware detection screens. Go to the Device Manager and start looking at "Resources" tabs (if present) for conflicts on each device. If the Resources tab says 'No Conflicts' move on. If conflicts are listed, go to the General Tab and check the box that says "Disable in this hardware profile." OR, remove the device and attempt to reinstall the driver. Read Larry's articles on solving resource conflicts.
If the registry restore doesn't work, then you need to come in under the radar, guns blazing, with a sneak attack. There are many ways to force SAFE mode. This is my favorite. This method requires a little more knowledge of DOS, and ability to edit the Autoexec.bat and Config.sys files.
SNEAK ATTACK: FORCE SAFE MODE BOOT USING WIN.COM /D: M
1) Insert the ESD and boot as before (without CD support) to the A:\> prompt.
2) Switch to the C:\> prompt (or the root directory of the active partition).
3) Type: edit autoexec.bat (You should see the blue screen of the DOS editor.)
4) Edit the 1st line as follows: C:\WINDOWS\ WIN /D: M
5) Win.com is usually in C:\WINDOWS. If not, you'll have to change the path above.
6) If there are other lines in the autoexec.bat file, type REM at the beginning of each line to temporarily disable it. Remember to remove these REMs when you finish trouble-shooting.
7) Likewise, edit the config.sys file. You may need to put some REMs there too, if you have entries.
8) Remove your ESD and push CTRL+ALT+DEL to reboot.
If this works, you will automatically boot into SAFE mode, and you can use Device Manager to resolve conflicts. If this doesn't work, then you have pretty serious problems and need to try Plan B.
Plan B involves some specialized case-bashing. Since I have no idea what kind of computer you have, you'll have to figure that one out for your self.