I'm going out on a limb here ( not really ) and say no they can't be upgraded in any meaningful way that's not a complete waste of time and money for you. Both those systems are completely obsolete to the point you almost could not give them away. A P4 1.7Ghz will not even be able to do high def video on youtube. An 8600GT is about as good as you are going to get without creating a huge bottleneck ( and you might be bottlenecking with that ) with the Sempron.
+1 thats where I was going to end up. The case, and HDD can be reused, maybe the PSU, but they tended to size them perfectly and no more. Actually the hdd being ide is probably junk too. Sorry, not the news you wanted.
It says it can run a an Athlon 64X2 dual core CPU. Socket AM2. Can a socket AM2+ cpu work? And if I do put another CPU in it what am I supposed to look for in the CPU I pick?I know I can find an Athlon 64X2 dual core on ebay. WOuld a 2.1 dual core be faster than a 2.1 single core? I do plan on getting a new PSU for the emachine since it is a 300w. I was going to try for a 400 or 450w one.
Also on the computer specs it say it can be upgraded to 2GB or Ram which I currently have it but on the motherboard specs it say 4GB of ram. So can I put 2 2gb ram in each slot as opposed to one?
I know you guys said these are too old to upgrade but they are not going to be used online for anything other than updates. These are just something for the kids to have around to play with. Nothing major.
I do know on the Dell I discovered I can only go up to 2 512MB of ram which it is at currently. I had read somewhere (but can't find it) that I could put a P4 2.5 in it as opposed to the 1.7 but I am not sure.
Edit: just found the notes I made on the Dell.
Motherboard is a 7W080 Socket 478 400mzh if that means anything.
In both cases, you would probably do yourself a favor by going with a new motherboard+CPU+RAM combo.
DDR2 is quite expensive these days, about twice as expensive as DDR3. If you are going to upgrade CPU + RAM, you may as well upgrade to a motherboard with DDR3 support in the process which is going to give you access to much more interesting CPU choices along with all the other benefits from having a modern platform for only $75 or so more.