All of a sudden my IBM ThinkPad only will boot in Safe Mode. Does anyone have an idea as to what's going on here?

What model/specs?
 
<A HREF="http://www.folken.net/myrig.htm" target="_new">My precious...</A>

1400i  2611
300MHz cpu
64 ram
 
Was just using the machine for dial-up e-mail.
Protected by Zone Alarm.
Was in use for 2 months or so; all of a sudden Friday AM, it booted itself into safe mode and that's all I could get out of it.

That is one way to stay secure, maybe it is a feature?
 
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And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>

Is it giving you some sort of message when trying to boot to windows?  I'm assuming it probably has 95 or 98 on it?
That install might have finally decided to give up, lol.
 
<A HREF="http://www.folken.net/myrig.htm" target="_new">My precious...</A>

Something about missing files; and then it goes into Safe.
OS is 98SE.

You should try reinstalling the OS.
 
Then again maybe you should look to see if there is a reason why the file went missing.
 
Try using  
 
Memtest86 to test your memory
Manufacturer's diagnostic utility to test your hard drive (extended tests).
 
If you memory and hard drive is fine try doing a repair installation (doesn't erase any files and most install apps will still work).

How long has it been since the last reformat?
 
<A HREF="http://www.folken.net/myrig.htm" target="_new">My precious...</A>

Thanks for all of your timely responses.
 
I reinstalled W98se and then the video drivers over. Everything seemed to be okay.
I checked for a virus-negative.
I MemTested the memory-okay.
I SpinRited the hd-okay.
 
I'm wondering if dirty electricity or the power supply starting to get funky would cause corruption?
 
Something obviously happened, which might remain a mystery. The last thing the machine did before it went bad was my wife going to the Babies-R-Us website to check out gifts.