Sorry for late reply.
Have you downloaded any patches? They can both be helpful but can also harm a little; for example, some patches don't like eachother = crash.
About your specs; PES should run on them. Have you installed the latest drivers for your computer?
What I would suggest to try: Do a complete reinstall; but turn off
your antivirus and UAC while doing that. Also, make sure that you are the Admin on your computer (kind of obvious...).
Tell us how you get on!