It is a mac and I have tried a few but they always want you to pay once they tell you that you have X number of viruses ,malware or suchget a program called CC Cleaner by piriform, it's free and has cleaning tools on it to help with PC housekeeping and a free program called smart defrag as I assume you have HDD drives and not solid state if it's 10 year old.
Do a bit of maintenance once a week and it'll run much smoother all the time. It takes 2 mins to clean with CC and defrag can run in the background.
We got this today lads and lasses, I know we can get over the line tonight and have faith we will.