I was using my power tower as usual, and today after double clicking on an icon, the watch cursor appears, and the computer freezes. It is running os9 I think.
Hopefully, pushing the reset button can make it boot up successfully.
If the problem ONLY occurs with the same icon, then it's software related (corrupted or incompatibility).
Otherwise, it could be a few things.
1. poor connectivity on RAM modules
2. poor connectivity on video card
3. poor connectivity on CPU card.
4. failed/failing HD or bad blocks on HD.
5. other - unknown.
To test the poor connectivity, boot the machine whilst holding down the shift key. You should see "Welcome to Macintosh" - "Extensions Disabled".
Wait until the computer finishes booting and no more HD seeking sound is heard.
Alternatively, if possible, boot up from a MacOS 8 or 9 CD.
Now, move the mouse and observe the mouse pointer on the screen. Continue to move the mouse in a constant circular motion, and gently rock each module from side to side. If the mouse pointer freezes on the screen, you'll need to clean the memory module's contacts, and possibly the socket's contacts.
Some mild contact cleaners can do the job, but the problem may return. Alcohol wipes (without any additives) can help.