I had one of those storefront computer hacks fix something once. He mentioned the capacitors.
The 4700c is over 15 years old and I have only had to replace the power supply one time.
Are you still getting the same effect on the screen when it freezes?
In that case, you might want to apply new thermal paste as I previously suggested since the system is using onboard video and the CPU might be overheating..
Are all drivers up-to-date?
Forum Member since 2004 I am not a Dell employee