1. Your original post really didn't have enough information to even begin to guess where
"the problem" might be, or what you could possibly do about it.
Please check out this link - I think it'll help:
"How To Ask Questions The Smart Way" by Eric Steven Raymond and Rick Moen.
2. As far as "getting more information", I'd start out with the program "top:
a) Start a command line session
<= DO THIS FIRST
b) Try to reproduce the problem (do whatever "makes the CPU go to 100%")
<= THE SYSTEM WILL PROBABLY SLOW TO A CRAWL
c) Type "top"
<= THIS WILL GIVE YOU A SUMMARY OF ALL PROCESSES RUNNING ON YOUR SYSTEM
d) Type "F" (to sort by column number), then select "%CPU"
e) Whatever process at the top might be showing "99% CPU" and, if so, is probably "the bad guy"
3. Post whatever additional information you find back to us here on LQ. We might be able to help.
Good luck .. PSM