You'll still have a bunch of crap in your registry leftover. This is 
because, as a matter of policy, software developers don't like to 
delete anything in the registry due to bugyness and liability reasons. 
Instead, they leave these broken links in the registry with no purpose 
other than to inflate the size of your registry, which in turn swallows 
valuable memory, which in turn hogs system resources and dogs your 
system. You'll of course have scattered DLLs sitting around also.

There are two methods of dealing with this. One is riskier but easier, 
the other is methodicaly pure but time intensive. The former is get a 
good registry cleaner and hun't for unneccessary DLLs. The best utility 
I know of is from McAfee. In fact, if you to their web site they will 
run all their utilities over the web, which is awesome. You have to pay 
a modest yearly membership fee, but you can get a free trial period.

The latter method is obviously hosing your system to flatline and reburning 
it. I do that to my system every six months and always enjoy performance 
increase afterwards, but maybe I'm a bit of a perfectionist.

If you don't have a backup device, then delete all program files that 
you're not going to need to backup. Move all data you need to save into
 a folder, then use PartitionMagic to create a separate partion space. 
Now move the backup folder into that separate partition space. Then 
format the first partition, reinstall. Now put your backup files into 
place so as to empty the second partition. Finally, use PartitionMagic 
to delete the second partition and expand the first partition to fill 
the drive again. You can get PartitionMagic from it's maker, PowerQuest.

A thing of note is that Windows 9x scans your hard drive upon install 
for old registry files. There is a bit of debate over how intensive the 
scan is. Back when I was a Windows support engineer for Microsoft, a 

strong rumor was that if your registry was on the drive, the installer 
would find it and assimilate it. The only way to be sure is to rename 
all registry files, or delete them. This means the backups as well. 
That includes system.1st, system.dat, user.dat, user.da0, and system.da0.

BTW, it's pretty easy to save all information regarding e-mail, favorites, 
address book, etc. You can save anything if you're determined enough. 
Feel free to ask me questions if you have any...

This concludes Chapter 1.