I have seen this problem before, and it wasn't memory.
The registry is a very complex collection of data, which can easily end up with a glitch or 2. Unfortunately, the default Windows 98 action, on finding a glitch, is to go back to the previous backup of the registry. If that also contained the problem or corruption, then you will continue doing this course of action every switch on.
The only way to sort it out is to manually fix the problem with the registry.
There are plenty of references in the previous posting to articles on using the registry tools, so start by using scanregw /scanonly .
If that identifies a problen, then carry on and use scanreg /fix
You might also try regclean
Having fixed the problem, make sure you do a backup by running scanreg /backup
These tools are inherently safe and easy to use, and should not cause any problems used in this manner.
The health warnings all apply to using regedit, which is much more dangerous and can really screw your system if used incorrectly.