It is a mini tower which has a core duo 2 e8400 processor in it now. I am currently in school studying web development and just purchased an old ProBook and just wanting something that will get me started in my new career. I have a very tight budget so money is a issue right now.
You need to talk to dell, and have them tell you which processors are compatible WITH THEIR BIOS. Then, you can select from those.
Personally, it does not make much sense to spend time, and money, on such an old machine (from 2008). And, it will still not be compatible with windows 10.