Old technology!

My old pc which I have retrieved from the roof after about 2 years! The reason - a friend needs to access some information which is on a back up disc but his computer has died. I was hoping that mine would work as I have the programme on this machine which is needed. It is no longer available and thus the need to try to get the old box working! So far not much success - tomorrow I'll take the side off and clean it and also spray all connections with electrical cleaner to see if that helps.......I really haven't a clue!