|Usually a hang is caused by something hardware related.|
REMOVE the power to your case/power supply.
Open up your case.
- a poor connection inside your case. Make sure all connectors and cards and the ram are properly seated. All data cables connected to hard drives capable of UDMA 66 or greater must be 80 wire ones. If in doubt, unplug, plug back in - be careful unplugging data cable connectors - if they are tight, pull on a strap if available rather than the cable itself if it has that, or pull on the center of the data cable - it is easy to rip the data cable and break wires if you pull on either side.
- a poor connection in your ram slots - See response 2 in this - try cleaning the contacts on the modules, etc.
- overheating of your cpu. Make sure the cpu fan and heat sink are reasonably clean.
When you boot with the case open, the cpu fan should spin the speed it is supposed to, and not make any rattling or screeching noises which are most likely to happen when the computer is booted after have being off for a long time. If you're not sure whether the cpu fan is spinning it's properly speed, look at the current rpm reading in the bios Setup hardware monitoring information when the computer is running - the rpm should not vary much. In the same place you can check whether the cpu temperature is reasonable - best done when the computer is thuroughly warmed up.
- if you have ever had to replace a defective cpu fan, the cpu may have been damaged while the cpu fan was defective.
- your power supply is defective. Failing power supplies are common and can cause your symptoms.
Check your PS.
Less likely but quite possible.....
- a CD drive that is starting to fail - e.g. you may get delays if there is a CD in the drive and the drive motor can no longer spin properly, or even without a CD in a drive if the logic board on the drive is defective - disconnect the data cable to the CD drive(s) and try your computer for a while.
- something on your computer was damaged by a power spike or surge and your computer was not protected from that, or is not protected from that now. Everything connected to your computer should be protected - including the AC supply to your printer, router, high speed modem, etc., and the cable that connects you to the internet and/or to a fax modem - coaxial or telephone.