Requesting solutionsWin98 problems

I am using Windows 98 SE since couple of years.After some time of
use,often windows gets corrupted.Then PC needs frequent rebooting or
else windows crashesh frequently or stops responding.
Inspite doing Scan Disk or Defrag,no significant improvement is seen.
In this case most of the software/hardware consultants advice to
format C drive and reinstall Win 98 SE.However this is very time
consuming and like a nightmare.
1.Which measures I should take to have hasslesfree performance
without format,rebooting and reinstallations?
2.Is there any FREE,but reliable registry Cleaner , if so where can I
get it?
Thank you in advance.
Dhananjay Pathak